Systems and methods for signaling picture information in a slice header in video coding

ABSTRACT

This disclosure relates to video coding and more particularly to techniques for signaling picture information in a slice header for coded video. According to an aspect of an invention, a first flag syntax element specifying whether a picture header is present in a slice header is parsed; a second flag syntax element, specifying a luma mapping is used for a current slice or a luma mapping with a chroma scalling is not used for a current slice, and a third flag syntax element, specifying whether a scaling information for the current slice is derived, are parsed based on the first flag syntax element.

TECHNICAL FIELD

This disclosure relates to video coding and more particularly to techniques for signaling picture information in a slice header for coded video.

BACKGROUND ART

Digital video capabilities can be incorporated into a wide range of devices, including digital televisions, laptop or desktop computers, tablet computers, digital recording devices, digital media players, video gaming devices, cellular telephones, including so-called smartphones, medical imaging devices, and the like. Digital video may be coded according to a video coding standard. Video coding standards define the format of a compliant bitstream encapsulating coded video data. A compliant bitstream is a data structure that may be received and decoded by a video decoding device to generate reconstructed video data. Video coding standards may incorporate video compression techniques. Examples of video coding standards include ISO/IEC MPEG-4 Visual and ITU-T H.264 (also known as ISO/IEC MPEG-4 AVC) and High-Efficiency Video Coding (HEVC). HEVC is described in High Efficiency Video Coding (HEVC), Rec. ITU-T H.265, December 2016, which is incorporated by reference, and referred to herein as ITU-T H.265. Extensions and improvements for ITU-T H.265 are currently being considered for the development of next generation video coding standards. For example, the ITU-T Video Coding Experts Group (VCEG) and ISO/IEC (Moving Picture Experts Group (MPEG) (collectively referred to as the Joint Video Exploration Team (JVET)) are working to standardize video coding technology with a compression capability that significantly exceeds that of ITU-T H.265. The Joint Exploration Model 7 (JEM 7), Algorithm Description of Joint Exploration Test Model 7 (JEM 7), ISO/IEC JTC1/SC29/WG11 Document: JVET-G1001, July 2017, Torino, IT, which is incorporated by reference herein, describes the coding features that were under coordinated test model study by the JVET as potentially enhancing video coding technology beyond the capabilities of ITU-T H.265. It should be noted that the coding features of JEM 7 are implemented in JEM reference software. As used herein, the term JEM may collectively refer to algorithms included in JEM 7 and implementations of JEM reference software. Further, in response to a “Joint Call for Proposals on Video Compression with Capabilities beyond HEVC,” jointly issued by VCEG and MPEG, multiple descriptions of video coding tools were proposed by various groups at the 10th Meeting of ISO/IEC JTC1/SC29/WG11 16-20 Apr. 2018, San Diego, Calif. From the multiple descriptions of video coding tools, a resulting initial draft text of a video coding specification is described in “Versatile Video Coding (Draft 1),” 10th Meeting of ISO/IEC JTC1/SC29/WG11 16-20 Apr. 2018, San Diego, Calif., document JVET-J1001-v2, which is incorporated by reference herein, and referred to as JVET-J1001. The current development of a next generation video coding standard by the VCEG and MPEG is referred to as the Versatile Video Coding (VVC) project. “Versatile Video Coding (Draft 8),” 17th Meeting of ISO/IEC JTC1/SC29/WG11 7-17 Jan. 2020, Brussel, BE, document JVET-Q2001-vB, which is incorporated by reference herein, and referred to as JVET-Q2001, represents the current iteration of the draft text of a video coding specification corresponding to the VVC project.

Video compression techniques enable data requirements for storing and transmitting video data to be reduced. Video compression techniques may reduce data requirements by exploiting the inherent redundancies in a video sequence. Video compression techniques may sub-divide a video sequence into successively smaller portions (i.e., groups of pictures within a video sequence, a picture within a group of pictures, regions within a picture, sub-regions within regions, etc.). Intra prediction coding techniques (e.g., spatial prediction techniques within a picture) and inter prediction techniques (i.e., inter-picture techniques (temporal)) may be used to generate difference values between a unit of video data to be coded and a reference unit of video data. The difference values may be referred to as residual data. Residual data may be coded as quantized transform coefficients. Syntax elements may relate residual data and a reference coding unit (e.g., intra-prediction mode indices and motion information). Residual data and syntax elements may be entropy coded. Entropy encoded residual data and syntax elements may be included in data structures forming a compliant bitstream.

SUMMARY OF INVENTION

In one example, a method of decoding video data comprises: receiving a slice header; parsing a first flag syntax element specifying whether a picture header is present in the slice header; parsing a second flag syntax element, specifying a luma mapping is used for a current slice or a luma mapping with a chroma scalling is not used for a current slice, based on the first flag syntax element; and parsing a third flag syntax element, specifying whether a scaling information for the current slice is derived, based on the first flag syntax element.

In one example, a method of encoding image data comprises: signaling a slice header; wherein: the slice header includes: (i) a first flag syntax element specifying whether a picture header is present in the slice header, (ii) a second flag syntax element, specifying a luma mapping is used for a current slice or a luma mapping with a chroma scalling is not used for a current slice, based on the first flag syntax element; and (iii) a third flag syntax element, specifying whether a scaling information for the current slice is derived, based on the first flag syntax element.

In one example, a device for decoding video data comprises: a processor, and a memory associated with the processor; wherein the processor is configured to perform the following steps: receiving a slice header; parsing a first flag syntax element specifying whether a picture header is present in the slice header; parsing a second flag syntax element, specifying a luma mapping is used for a current slice or a luma mapping with a chroma scalling is not used for a current slice, based on the first flag syntax element; and parsing a third flag syntax element, specifying whether a scaling information for the current slice is derived, based on the first flag syntax element.

In one example, a device for encoding image data comprises: a processor, and a memory associated with the processor; wherein the processor is configured to perform the following steps: signaling a slice header, wherein the slice header includes: (i) a first flag syntax element specifying whether a picture header is present in the slice header, (ii) a second flag syntax element, specifying a luma mapping is used for a current slice or a luma mapping with a chroma scalling is not used for a current slice, based on the first flag syntax element; and (iii) a third flag syntax element, specifying whether a scaling information for the current slice is derived, based on the first flag syntax element.

The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating an example of a system that may be configured to encode and decode video data according to one or more techniques of this disclosure.

FIG. 2 is a conceptual diagram illustrating coded video data and corresponding data structures according to one or more techniques of this disclosure.

FIG. 3 is a conceptual diagram illustrating a data structure encapsulating coded video data and corresponding metadata according to one or more techniques of this disclosure.

FIG. 4 is a conceptual drawing illustrating an example of components that may be included in an implementation of a system that may be configured to encode and decode video data according to one or more techniques of this disclosure.

FIG. 5 is a block diagram illustrating an example of a video encoder that may be configured to encode video data according to one or more techniques of this disclosure.

FIG. 6 is a block diagram illustrating an example of a video decoder that may be configured to decode video data according to one or more techniques of this disclosure.

DESCRIPTION OF EMBODIMENTS

In general, this disclosure describes various techniques for coding video data. In particular, this disclosure describes techniques for signaling picture information in a slice header for coded video data. Picture information may include information indicating whether one or more video coding tools (e.g., prediction techniques, filtering techniques, etc.) are enabled for a picture and/or portions thereof. It should be noted that although techniques of this disclosure are described with respect to ITU-T H.264, ITU-T H.265, JEM, and JVET-Q2001, the techniques of this disclosure are generally applicable to video coding. For example, the coding techniques described herein may be incorporated into video coding systems, (including video coding systems based on future video coding standards) including video block structures, intra prediction techniques, inter prediction techniques, transform techniques, filtering techniques, and/or entropy coding techniques other than those included in ITU-T H.265, JEM, and JVET-Q2001. Thus, reference to ITU-T H.264, ITU-T H.265, JEM, and/or JVET-Q2001 is for descriptive purposes and should not be construed to limit the scope of the techniques described herein. Further, it should be noted that incorporation by reference of documents herein is for descriptive purposes and should not be construed to limit or create ambiguity with respect to terms used herein. For example, in the case where an incorporated reference provides a different definition of a term than another incorporated reference and/or as the term is used herein, the term should be interpreted in a manner that broadly includes each respective definition and/or in a manner that includes each of the particular definitions in the alternative.

Video content includes video sequences comprised of a series of frames (or pictures). A series of frames may also be referred to as a group of pictures (GOP). Each video frame or picture may divided into one or more regions. Regions may be defined according to a base unit (e.g., a video block) and sets of rules defining a region. For example, a rule defining a region may be that a region must be an integer number of video blocks arranged in a rectangle. Further, video blocks in a region may be ordered according to a scan pattern (e.g., a raster scan). As used herein, the term video block may generally refer to an area of a picture or may more specifically refer to the largest array of sample values that may be predictively coded, sub-divisions thereof, and/or corresponding structures. Further, the term current video block may refer to an area of a picture being encoded or decoded. A video block may be defined as an array of sample values. It should be noted that in some cases pixel values may be described as including sample values for respective components of video data, which may also be referred to as color components, (e.g., luma (Y) and chroma (Cb and Cr) components or red, green, and blue components). It should be noted that in some cases, the terms pixel value and sample value are used interchangeably. Further, in some cases, a pixel or sample may be referred to as a pel. A video sampling format, which may also be referred to as a chroma format, may define the number of chroma samples included in a video block with respect to the number of luma samples included in a video block. For example, for the 4:2:0 sampling format, the sampling rate for the luma component is twice that of the chroma components for both the horizontal and vertical directions.

A video encoder may perform predictive encoding on video blocks and sub-divisions thereof. Video blocks and sub-divisions thereof may be referred to as nodes. ITU-T H.264 specifies a macroblock including 16×16 luma samples. That is, in ITU-T H.264, a picture is segmented into macroblocks. ITU-T H.265 specifies an analogous Coding Tree Unit (CTU) structure (which may be referred to as a largest coding unit (LCU)).

In ITU-T H.265, pictures are segmented into CTUs. In ITU-T H.265, for a picture, a CTU size may be set as including 16×16, 32×32, or 64×64 luma samples. In ITU-T H.265, a CTU is composed of respective Coding Tree Blocks (CTB) for each component of video data (e.g., luma (Y) and chroma (Cb and Cr). It should be noted that video having one luma component and the two corresponding chroma components may be described as having two channels, i.e., a luma channel and a chroma channel.

Further, in ITU-T H.265, a CTU may be partitioned according to a quadtree (QT) partitioning structure, which results in the CTBs of the CTU being partitioned into Coding Blocks (CB). That is, in ITU-T H.265, a CTU may be partitioned into quadtree leaf nodes. According to ITU-T H.265, one luma CB together with two corresponding chroma CBs and associated syntax elements are referred to as a coding unit (CU). In ITU-T H.265, a minimum allowed size of a CB may be signaled. In ITU-T H.265, the smallest minimum allowed size of a luma CB is 8×8 luma samples. In ITU-T H.265, the decision to code a picture area using intra prediction or inter prediction is made at the CU level.

In ITU-T H.265, a CU is associated with a prediction unit structure having its root at the CU. In ITU-T H.265, prediction unit structures allow luma and chroma CBs to be split for purposes of generating corresponding reference samples. That is, in ITU-T H.265, luma and chroma CBs may be split into respective luma and chroma prediction blocks (PBs), where a PB includes a block of sample values for which the same prediction is applied. In ITU-T H.265, a CB may be partitioned into 1, 2, or 4 PBs. ITU-T H.265 supports PB sizes from 64×64 samples down to 4×4 samples. In ITU-T H.265, square PBs are supported for intra prediction, where a CB may form the PB or the CB may be split into four square PBs. In ITU-T H.265, in addition to the square PBs, rectangular PBs are supported for inter prediction, where a CB may behalved vertically or horizontally to form PBs. Further, it should be noted that in ITU-T H.265, for inter prediction, four asymmetric PB partitions are supported, where the CB is partitioned into two PBs at one quarter of the height (at the top or the bottom) or width (at the left or the right) of the CB. Intra prediction data (e.g., intra prediction mode syntax elements) or inter prediction data (e.g., motion data syntax elements) corresponding to a PB is used to produce reference and/or predicted sample values for the PB.

JEM specifies a CTU having a maximum size of 256×256 luma samples. JEM specifies a quadtree plus binary tree (QTBT) block structure. In JEM, the QTBT structure enables quadtree leaf nodes to be further partitioned by a binary tree (BT) structure. That is, in JEM, the binary tree structure enables quadtree leaf nodes to be recursively divided vertically or horizontally. In JVET-Q2001, CTUs are partitioned according a quadtree plus multi-type tree (QTMT or QT+MTT) structure. The QTMT in JVET-Q2001 is similar to the QTBT in JEM. However, in JVET-Q2001, in addition to indicating binary splits, the multi-type tree may indicate so-called ternary (or triple tree (TT)) splits. A ternary split divides a block vertically or horizontally into three blocks. In the case of a vertical TT split, a block is divided at one quarter of its width from the left edge and at one quarter its width from the right edge and in the case of a horizontal TT split a block is at one quarter of its height from the top edge and at one quarter of its height from the bottom edge.

As described above, each video frame or picture may be divided into one or more regions. For example, according to ITU-T H.265, each video frame or picture may be partitioned to include one or more slices and further partitioned to include one or more tiles, where each slice includes a sequence of CTUs (e.g., in raster scan order) and where a tile is a sequence of CTUs corresponding to a rectangular area of a picture. It should be noted that a slice, in ITU-T H.265, is a sequence of one or more slice segments starting with an independent slice segment and containing all subsequent dependent slice segments (if any) that precede the next independent slice segment (if any). A slice segment, like a slice, is a sequence of CTUs. Thus, in some cases, the terms slice and slice segment may be used interchangeably to indicate a sequence of CTUs arranged in a raster scan order. Further, it should be noted that in ITU-T H.265, a tile may consist of CTUs contained in more than one slice and a slice may consist of CTUs contained in more than one tile. However, ITU-T H.265 provides that one or both of the following conditions shall be fulfilled: (1) All CTUs in a slice belong to the same tile; and (2) All CTUs in a tile belong to the same slice.

With respect to JVET-Q2001, slices are required to consist of an integer number of complete tiles or an integer number of consecutive complete CTU rows within a tile, instead of only being required to consist of an integer number of CTUs. It should be noted that in JVET-Q2001, the slice design does not include slice segments (i.e., no independent/dependent slice segments). Thus, in JVET-Q2001, a picture may include a single tile, where the single tile is contained within a single slice or a picture may include multiple tiles where the multiple tiles (or CTU rows thereof) may be contained within one or more slices. In JVET-Q2001, the partitioning of a picture into tiles is specified by specifying respective heights for tile rows and respective widths for tile columns. Thus, in JVET-Q2001 a tile is a rectangular region of CTUs within a particular tile row and a particular tile column position. Further, it should be noted that JVET-Q2001 provides where a picture may be partitioned into subpictures, where a subpicture is a rectangular region of a CTUs within a picture. The top-left CTU of a subpicture may be located at any CTU position within a picture with subpictures being constrained to include one or more slices. Thus, unlike a tile, a subpicture is not necessarily limited to a particular row and column position. It should be noted that subpictures may be useful for encapsulating regions of interest within a picture and a sub-bitstream extraction process may be used to only decode and display a particular region of interest. That is, as described in further detail below, a bitstream of coded video data includes a sequence of network abstraction layer (NAL) units, where a NAL unit encapsulates coded video data, (i.e., video data corresponding to a slice of picture) or a NAL unit encapsulates metadata used for decoding video data (e.g., a parameter set) and a sub-bitstream extraction process forms a new bitstream by removing one or more NAL units from a bitstream.

FIG. 2 is a conceptual diagram illustrating an example of a picture within a group of pictures partitioned according to tiles, slices, and subpictures. It should be noted that the techniques described herein may be applicable to tiles, slices, subpictures, subdivisions thereof and/or equivalent structures thereto. That is, the techniques described herein may be generally applicable regardless of how a picture is partitioned into regions. For example, in some cases, the techniques described herein may be applicable in cases where a tile may be partitioned into so-called bricks, where a brick is a rectangular region of CTU rows within a particular tile. Further, for example, in some cases, the techniques described herein may be applicable in cases where one or more tiles may be included in so-called tile groups, where a tile group includes an integer number of adjacent tiles. In one example, a tile group may be called a slice. In the example illustrated in FIG. 2 , Pic₃ is illustrated as including 16 tiles (i.e., Tile₀ to Tile₁₅) and three slices (i.e., Slice® to Slice₂). In the example illustrated in FIG. 2 , Slice® includes four tiles (i.e., Tile₀ to Tile₃), Slice₁ includes eight tiles (i.e., Tile₄ to Tile₁₁), and Slice₂ includes four tiles (i.e., Tile₁₂ to Tile₁₅). Further, as illustrated in the example of FIG. 2 , Pic₃ is illustrated as including two subpictures (i.e., Subpicture₀ and Subpicture)), where Subpicture₀ includes Slice® and Slice₁ and where Subpicture₁ includes Slice₂. As described above, subpictures may be useful for encapsulating regions of interest within a picture and a sub-bitstream extraction process may be used in order to selectively decode (and display) a region interest. For example, referring to FIG. 2 , Subpicture₀ may corresponding to an action portion of a sporting event presentation (e.g., a view of the field) and Subpicture₁ may corresponding to a scrolling banner displayed during the sporting event presentation. By using organizing a picture into subpictures in this manner, a viewer may be able to disable the display of the scrolling banner. That is, through a sub-bitstream extraction process Slice₂ NAL unit may be removed from a bitstream (and thus not decoded) and Slice® NAL unit and Slice_(r) NAL unit may be decoded and displayed. The encapsulation of slices of a picture into respective NAL unit data structures and sub-bitstream extraction are described in further detail below.

For intra prediction coding, an intra prediction mode may specify the location of reference samples within a picture. In ITU-T H.265, defined possible intra prediction modes include a planar (i.e., surface fitting) prediction mode, a DC (i.e., flat overall averaging) prediction mode, and 33 angular prediction modes (predMode: 2-34). In JEM, defined possible intra-prediction modes include a planar prediction mode, a DC prediction mode, and 65 angular prediction modes. It should be noted that planar and DC prediction modes may be referred to as non-directional prediction modes and that angular prediction modes may be referred to as directional prediction modes. It should be noted that the techniques described herein may be generally applicable regardless of the number of defined possible prediction modes.

For inter prediction coding, a reference picture is determined and a motion vector (MV) identifies samples in the reference picture that are used to generate a prediction for a current video block. For example, a current video block may be predicted using reference sample values located in one or more previously coded picture(s) and a motion vector is used to indicate the location of the reference block relative to the current video block. A motion vector may describe, for example, a horizontal displacement component of the motion vector (i.e., MV_(x)), a vertical displacement component of the motion vector (i.e., MV_(y)), and a resolution for the motion vector (e.g., one-quarter pixel precision, one-half pixel precision, one-pixel precision, two-pixel precision, four-pixel precision). Previously decoded pictures, which may include pictures output before or after a current picture, may be organized into one or more to reference pictures lists and identified using a reference picture index value. Further, in inter prediction coding, uni-prediction refers to generating a prediction using sample values from a single reference picture and bi-prediction refers to generating a prediction using respective sample values from two reference pictures. That is, in uniprediction, a single reference picture and corresponding motion vector are used to generate a prediction for a current video block and in bi-prediction, a first reference picture and corresponding first motion vector and a second reference picture and corresponding second motion vector are used to generate a prediction for a current video block. In bi-prediction, respective sample values are combined (e.g., added, rounded, and clipped, or averaged according to weights) to generate a prediction. Pictures and regions thereof may be classified based on which types of prediction modes may be utilized for encoding video blocks thereof. That is, for regions having a B type (e.g., a B slice), bi-prediction, uni-prediction, and intra prediction modes may be utilized, for regions having a P type (e.g., a P slice), uni-prediction, and intra prediction modes may be utilized, and for regions having an I type (e.g., an I slice), only intra prediction modes may be utilized. As described above, reference pictures are identified through reference indices. For example, for a P slice, there may be a single reference picture list, RefPicList0 and for a B slice, there may be a second independent reference picture list, RefPicList1, in addition to RefPicList0. It should be noted that for uni-prediction in a B slice, one of RefPicList0 or RefPicList1 may be used to generate a prediction. Further, it should be noted that during the decoding process, at the onset of decoding a picture, reference picture list(s) are generated from previously decoded pictures stored in a decoded picture buffer (DPB).

Further, a coding standard may support various modes of motion vector prediction. Motion vector prediction enables the value of a motion vector for a current video block to be derived based on another motion vector. For example, a set of candidate blocks having associated motion information may be derived from spatial neighboring blocks and temporal neighboring blocks to the current video block. Further, generated (or default) motion information may be used for motion vector prediction. Examples of motion vector prediction include advanced motion vector prediction (AMVP), temporal motion vector prediction (TMVP), so-called “merge” mode, and “skip” and “direct” motion inference. Further, other examples of motion vector prediction include advanced temporal motion vector prediction (ATMVP) and Spatial-temporal motion vector prediction (STMVP). For motion vector prediction, both a video encoder and video decoder perform the same process to derive a set of candidates. Thus, for a current video block, the same set of candidates is generated during encoding and decoding.

As described above, for inter prediction coding, reference samples in a previously coded picture are used for coding video blocks in a current picture. Previously coded pictures which are available for use as reference when coding a current picture are referred as reference pictures. It should be noted that the decoding order does not necessary correspond with the picture output order, i.e., the temporal order of pictures in a video sequence. In ITU-T H.265, when a picture is decoded it is stored to a decoded picture buffer (DPB) (which may be referred to as frame buffer, a reference buffer, a reference picture buffer, or the like). In ITU-T H.265, pictures stored to the DPB are removed from the DPB when they been output and are no longer needed for coding subsequent pictures. In ITU-T H.265, a determination of whether pictures should be removed from the DPB is invoked once per picture, after decoding a slice header, i.e., at the onset of decoding a picture. For example, referring to FIG. 2 , Pic₂ is illustrated as referencing Pic₁. Similarly, Pic₃ is illustrated as referencing Pic₀. With respect to FIG. 2 , assuming the picture number corresponds to the decoding order, the DPB would be populated as follows: after decoding Pic₀, the DPB would include {Pic₀}; at the onset of decoding Pic₁, the DPB would include {Pic₀}; after decoding Pic₁, the DPB would include {Pic₀, Pic₁}; at the onset of decoding Pic₂, the DPB would include {Pic₀, Pic₁}. Pic₂ would then be decoded with reference to Pic₁ and after decoding Pic₂, the DPB would include {Pic₀, Pic₁, Pic₂}. At the onset of decoding Pic₃, pictures Pic₀ and Pic₁ would be marked for removal from the DPB, as they are not needed for decoding Pic₃ (or any subsequent pictures, not shown) and assuming Pic₁ and Pic₂ have been output, the DPB would be updated to include {Pic₀}. Pic₃ would then be decoded by referencing Pic₀. The process of marking pictures for removal from a DPB may be referred to as reference picture set (RPS) management.

As described above, intra prediction data or inter prediction data is used to produce reference sample values for a block of sample values. The difference between sample values included in a current PB, or another type of picture area structure, and associated reference samples (e.g., those generated using a prediction) may be referred to as residual data. Residual data may include respective arrays of difference values corresponding to each component of video data. Residual data may be in the pixel domain. A transform, such as, a discrete cosine transform (DCT), a discrete sine transform (DST), an integer transform, a wavelet transform, or a conceptually similar transform, may be applied to an array of difference values to generate transform coefficients. It should be noted that in ITU-T H.265 and JVET-Q2001, a CU is associated with a transform tree structure having its root at the CU level. The transform tree is partitioned into one or more transform units (TUs). That is, an array of difference values may be partitioned for purposes of generating transform coefficients (e.g., four 8×8 transforms may be applied to a 16×16 array of residual values). For each component of video data, such sub-divisions of difference values may be referred to as Transform Blocks (TBs). It should be noted that in some cases, a core transform and a subsequent secondary transforms may be applied (in the video encoder) to generate transform coefficients. For a video decoder, the order of transforms is reversed.

A quantization process may be performed on transform coefficients or residual sample values directly (e.g., in the case, of palette coding quantization). Quantization approximates transform coefficients by amplitudes restricted to a set of specified values. Quantization essentially scales transform coefficients in order to vary the amount of data required to represent a group of transform coefficients. Quantization may include division of transform coefficients (or values resulting from the addition of an offset value to transform coefficients) by a quantization scaling factor and any associated rounding functions (e.g., rounding to the nearest integer). Quantized transform coefficients may be referred to as coefficient level values. Inverse quantization (or “dequantization”) may include multiplication of coefficient level values by the quantization scaling factor, and any reciprocal rounding or offset addition operations. It should be noted that as used herein the term quantization process in some instances may refer to division by a scaling factor to generate level values and multiplication by a scaling factor to recover transform coefficients in some instances. That is, a quantization process may refer to quantization in some cases and inverse quantization in some cases. Further, it should be noted that although in some of the examples below quantization processes are described with respect to arithmetic operations associated with decimal notation, such descriptions are for illustrative purposes and should not be construed as limiting. For example, the techniques described herein may be implemented in a device using binary operations and the like. For example, multiplication and division operations described herein may be implemented using bit shifting operations and the like.

Quantized transform coefficients and syntax elements (e.g., syntax elements indicating a coding structure for a video block) may be entropy coded according to an entropy coding technique. An entropy coding process includes coding values of syntax elements using lossless data compression algorithms. Examples of entropy coding techniques include content adaptive variable length coding (CAVLC), context adaptive binary arithmetic coding (CABAC), probability interval partitioning entropy coding (PIPE), and the like. Entropy encoded quantized transform coefficients and corresponding entropy encoded syntax elements may form a compliant bitstream that can be used to reproduce video data at a video decoder. An entropy coding process, for example, CABAC, may include performing a binarization on syntax elements. Binarization refers to the process of converting a value of a syntax element into a series of one or more bits. These bits may be referred to as “bins.” Binarization may include one or a combination of the following coding techniques: fixed length coding, unary coding, truncated unary coding, truncated Rice coding, Golomb coding, k-th order exponential Golomb coding, and Golomb-Rice coding. For example, binarization may include representing the integer value of 5 for a syntax element as 00000101 using an 8-bit fixed length binarization technique or representing the integer value of 5 as 11110 using a unary coding binarization technique. As used herein each of the terms fixed length coding, unary coding, truncated unary coding, truncated Rice coding, Golomb coding, k-th order exponential Golomb coding, and Golomb-Rice coding may refer to general implementations of these techniques and/or more specific implementations of these coding techniques. For example, a Golomb-Rice coding implementation may be specifically defined according to a video coding standard. In the example of CABAC, for a particular bin, a context provides a most probable state (MPS) value for the bin (i.e., an MPS for a bin is one of 0 or 1) and a probability value of the bin being the MPS or the least probably state (LPS). For example, a context may indicate, that the MPS of a bin is 0 and the probability of the bin being 1 is 0.3. It should be noted that a context may be determined based on values of previously coded bins including bins in the current syntax element and previously coded syntax elements. For example, values of syntax elements associated with neighboring video blocks may be used to determine a context for a current bin.

With respect to the equations used herein, the following arithmetic operators may be used:

-   + Addition -   − Subtraction -   * Multiplication, including matrix multiplication -   x^(y) Exponentiation. Specifies x to the power of y. In other     contexts, such notation is used for superscripting not intended for     interpretation as exponentiation. -   / Integer division with truncation of the result toward zero. For     example, 7/4 and −7/−4 are truncated to 1 and −7/4 and 7/−4 are     truncated to −1. -   ÷ Used to denote division in mathematical equations where no     truncation or rounding is intended.

$\frac{x}{y}$

-   Used to denote division in mathematical equations where no     truncation or rounding is intended.

Further, the following mathematical functions may be used:

-   -   Log 2(x) the base-2 logarithm of x;

${{Min}\left( {x,y} \right)} = \left\{ {\begin{matrix} {x;{x<=y}} \\ {y;{x > y}} \end{matrix};} \right.$ ${{Max}\left( {x,y} \right)} = \left\{ \begin{matrix} {x;{x>=y}} \\ {y;{x < y}} \end{matrix} \right.$

-   -   Ceil(x) the smallest integer greater than or equal to x.

With respect to the example syntax used herein, the following definitions of logical operators may be applied:

-   -   x && y Boolean logical “and” of x and y     -   x∥y Boolean logical “or” of x and y     -   ! Boolean logical “not”     -   x ? y: z If x is TRUE, evaluates to the value of y; otherwise,         evaluates to the value of z.

Further, the following relational operators may be applied:

-   -   > Greater than     -   >= Greater than or equal to     -   < Less than     -   <= Less than or equal to     -   == Equal to     -   != Not equal to

Further, it should be noted that in the syntax descriptors used herein, the following descriptors may be applied:

-   -   ac(v): context-adaptive arithmetic entropy-coded syntax element.     -   b(8): byte having any pattern of bit string (8 bits). The         parsing process for this descriptor is specified by the return         value of the function read_bits(8).     -   f(n): fixed-pattern bit string using n bits written (from left         to right) with the left bit first. The parsing process for this         descriptor is specified by the return value of the function         read_bits(n).     -   i(n): signed integer using n bits. When n is “v” in the syntax         table, the number of bits varies in a manner dependent on the         value of other syntax elements. The parsing process for this         descriptor is specified by the return value of the function         read_bits(n) interpreted as a two's complement integer         representation with most significant bit written first.     -   se(v): signed integer 0-th order Exp-Golomb-coded syntax element         with the left bit first.     -   u(n): unsigned integer using n bits. When n is “v” in the syntax         table, the number of bits varies in a manner dependent on the         value of other syntax elements. The parsing process for this         descriptor is specified by the return value of the function         read_bits(n) interpreted as a binary representation of an         unsigned integer with most significant bit written first.     -   ue(v): unsigned integer 0-th order Exp-Golomb-coded syntax         element with the left bit first.

As described above, video content includes video sequences comprised of a series of pictures and each picture may be divided into one or more regions. In JVET-Q2001, a coded representation of a picture comprises VCL NAL units of a particular layer within an AU and contains all CTUs of the picture. For example, referring again to FIG. 2 , the coded representation of Pic_(a) is encapsulated in three coded slice NAL units (i.e., Slice® NAL unit, Slice_(r) NAL unit, and Slice₂ NAL unit). It should be noted that the term video coding layer (VCL) NAL unit is used as a collective term for coded slice NAL units, i.e., VCL NAL is a collective term which includes all types of slice NAL units. As described above, and in further detail below, a NAL unit may encapsulate metadata used for decoding video data. A NAL unit encapsulating metadata used for decoding a video sequence is generally referred to as a non-VCL NAL unit. Thus, in JVET-Q2001, a NAL unit may be a VCL NAL unit or a non-VCL NAL unit. It should be noted that a VCL NAL unit includes slice header data, which provides information used for decoding the particular slice. Thus, in JVET-Q2001, information used for decoding video data, which may be referred to as metadata in some cases, is not limited to being included in non-VCL NAL units. JVET-Q2001 provides where a picture unit (PU) is a set of NAL units that are associated with each other according to a specified classification rule, are consecutive in decoding order, and contain exactly one coded picture and where an access unit (AU) is a set of PUs that belong to different layers and contain coded pictures associated with the same time for output from the DPB. JVET-Q2001 further provides where a layer is a set of VCL NAL units that all have a particular value of a layer identifier and the associated non-VCL NAL units. Further, in JVET-Q2001, a PU consists of zero or one PH NAL units, one coded picture, which comprises of one or more VCL NAL units, and zero or more other non-VCL NAL units. Further, in JVET-Q2001, a coded video sequence (CVS) is a sequence of AUs that consists, in decoding order, of a CVSS AU, followed by zero or more AUs that are not CVSS AUs, including all subsequent AUs up to but not including any subsequent AU that is a CVSS AU, where a coded video sequence start (CVSS) AU is an AU in which there is a PU for each layer in the CVS and the coded picture in each present picture unit is a coded layer video sequence start (CLVSS) picture. In JVET-Q2001, a coded layer video sequence (CLVS) is a sequence of PUs within the same layer that consists, in decoding order, of a CLVSS PU, followed by zero or more PUs that are not CLVSS PUs, including all subsequent PUs up to but not including any subsequent PU that is a CLVSS PU. This is, in JVET-Q2001, a bitstream may be described as including a sequence of AUs forming one or more CVSs.

Multi-layer video coding enables a video presentation to be decoded/displayed as a presentation corresponding to a base layer of video data and decoded/displayed one or more additional presentations corresponding to enhancement layers of video data. For example, a base layer may enable a video presentation having a basic level of quality (e.g., a High Definition rendering and/or a 30 Hz frame rate) to be presented and an enhancement layer may enable a video presentation having an enhanced level of quality (e.g., an Ultra High Definition rendering and/or a 60 Hz frame rate) to be presented. An enhancement layer may be coded by referencing a base layer. That is, for example, a picture in an enhancement layer may be coded (e.g., using inter-layer prediction techniques) by referencing one or more pictures (including scaled versions thereof) in a base layer. It should be noted that layers may also be coded independent of each other. In this case, there may not be inter-layer prediction between two layers. Each NAL unit may include an identifier indicating a layer of video data the NAL unit is associated with. As described above, a sub-bitstream extraction process may be used to only decode and display a particular region of interest of a picture. Further, a sub-bitstream extraction process may be used to only decode and display a particular layer of video. Sub-bitstream extraction may refer to a process where a device receiving a compliant or conforming bitstream forms a new compliant or conforming bitstream by discarding and/or modifying data in the received bitstream. For example, sub-bitstream extraction may be used to form a new compliant or conforming bitstream corresponding to a particular representation of video (e.g., a high quality representation).

In JVET-Q2001, each of a video sequence, a GOP, a picture, a slice, and CTU may be associated with metadata that describes video coding properties and some types of metadata an encapsulated in non-VCL NAL units. JVET-Q2001 defines parameters sets that may be used to describe video data and/or video coding properties. In particular, JVET-Q2001 includes the following four types of parameter sets: video parameter set (VPS), sequence parameter set (SPS), picture parameter set (PPS), and adaption parameter set (APS), where a SPS applies to apply to zero or more entire CVSs, a PPS applies to zero or more entire coded pictures, a APS applies to zero or more slices, and a VPS may be optionally referenced by a SPS. A PPS applies to an individual coded picture that refers to it. In JVET-Q2001, parameter sets may be encapsulated as a non-VCL NAL unit and/or may be signaled as a message. JVET-Q2001 also includes a picture header (PH) which is encapsulated as a non-VCL NAL unit. In JVET-Q2001, a picture header applies to all slices of a coded picture. JVET-Q2001 further enables decoding capability information (DCI) and supplemental enhancement information (SEI) messages to be signaled. In JVET-Q2001, DCI and SEI messages assist in processes related to decoding, display or other purposes, however, DCI and SEI messages may not be required for constructing the luma or chroma samples according to a decoding process. In JVET-Q2001, DCI and SEI messages may be signaled in a bitstream using non-VCL NAL units. Further, DCI and SEI messages may be conveyed by some mechanism other than by being present in the bitstream (i.e., signaled out-of-band).

FIG. 3 illustrates an example of a bitstream including multiple CVSs, where a CVS includes AUs, and AUs include picture units. The example illustrated in FIG. 3 corresponds to an example of encapsulating the slice NAL units illustrated in the example of FIG. 2 in a bitstream. In the example illustrated in FIG. 3 , the corresponding picture unit for Pic₃ includes the three VCL NAL coded slice NAL units, i.e., Slice® NAL unit, Slice₁ NAL unit, and Slice₂ NAL unit and two non-VCL NAL units, i.e., a PPS NAL Unit and a PH NAL unit. It should be noted that in FIG. 3 , HEADER is a NAL unit header (i.e., not to be confused with a slice header). Further, it should be noted that in FIG. 3 , other non-VCL NAL units, which are not illustrated may be included in the CVSs, e.g., SPS NAL units, VPS NAL units, SEI message NAL units, etc. Further, it should be noted that in other examples, a PPS NAL Unit used for decoding Pic₃ may be included elsewhere in the bitstream, e.g., in the picture unit corresponding to Pic₀ or may be provided by an external mechanism. As described in further detail below, in JVET-Q2001, a PH syntax structure may be present in the slice header of a VCL NAL unit or in a PH NAL unit of the current PU.

JVET-Q2001 defines NAL unit header semantics that specify the type of Raw Byte Sequence Payload (RBSP) data structure included in the NAL unit. Table 1 illustrates the syntax of the NAL unit header provided in JVET-Q2001.

TABLE 1 De- scrip- tor nal_unit_header( ) {  forbidden_zero_bit f(1)  nuh_reserved_zero_bit u(1)  nuh_layer_id u(6)  nal_unit_type u(5)  nuh_temporal_id_plus1 u(3) }

JVET-Q2001 provides the following definitions for the respective syntax elements illustrated in Table 1.

forbidden_zero_bit shall be equal to 0. nuh_reserved_zero_bit shall be equal to ‘0’. The value 1 of nuh_reserved_zero_bit may be specified in the future by ITU-T|ISO/IEC. Decoders shall ignore (i.e. remove from the bitstream and discard) NAL units with nuh_reserved_zero_bit equal to ‘1’. nuh_layer_id specifies the identifier of the layer to which a VCL NAL unit belongs or the identifier of a layer to which a non-VCL NAL unit applies. The value of nuh_layer_id shall be in the range of 0 to 55, inclusive. Other values for nuh_layer_id are reserved for future use by ITU-T|ISO/IEC.

The value of nuh_layer_id shall be the same for all VCL NAL units of a coded picture. The value of nuh_layer_id of a coded picture or a PU is the value of the nuh_layer_id of the VCL NAL units of the coded picture or the PU.

The value of nuh_layer_id for AUD, PH, EOS, and FD NAL units is constrained as follows:

-   -   If nal_unit_type is equal to AUD_NUT, nuh_layer_id shall be         equal to vps_layer_id[0].     -   Otherwise, when nal_unit_type is equal to PH_NUT, EOS NUT, or         FD_NUT, nuh_layer_id shall be equal to the nuh_layer_id of         associated VCL NAL unit.         NOTE—The value of nuh_layer_id of DCI, VPS, and EOB NAL units is         not constrained.

The value of nal_unit_type shall be the same for all pictures of a CVSS AU.

nuh_temporal_id_plus1 minus1 specifies a temporal identifier for the NAL unit.

The value of nuh_temporal_id_plus1 shall not be equal to 0.

The variable Temporand is derived as follows:

-   -   TemporalId=nuh_temporal_id_plus1−1

When nal_unit_type is in the range of IDR_W_RADL to RSV_IRAP_12, inclusive, TemporalId shall be equal to 0.

When nal_unit_type is equal to STSA_NUT and vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id] ] is equal to 1, TemporalId shall not be equal to 0.

The value of TemporalId shall be the same for all VCL NAL units of an AU. The value of TemporalId of a coded picture, a PU, or an AU is the value of the TemporalId of the VCL NAL units of the coded picture, PU, or AU. The value of TemporalId of a sublayer representation is the greatest value of TemporalId of all VCL NAL units in the sublayer representation.

The value of TemporalId for non-VCL NAL units is constrained as follows:

-   -   If nal_unit_type is equal to DCI_NUT, VPS_NUT, or VPS_NUT,         TemporalId shall be equal to 0 and the TemporalId of the AU         containing the NAL unit shall be equal to 0.     -   Otherwise, if nal_unit_type is equal to PH_NUT, TemporalId shall         be equal to the TemporalId of the PU containing the NAL unit.     -   Otherwise, if nal_unit_type is equal to EOS NUT or EOB NUT,         TemporalId shall be equal to 0.     -   Otherwise, if nal_unit_type is equal to AUD_NUT, FD NUT,         PREFIX_SEI_NUT, or SUFFIX_SEI_NUT, TemporalId shall be equal to         the TemporalId of the AU containing the NAL unit.     -   Otherwise, when nal_unit_type is equal to PPS_NUT.         PREFIX_APS_NUT, or SUFFIX_APS_NUT, TemporalId shall be greater         than or equal to the TemporalId of the PU containing the NAL         unit.         NOTE—When the NAL unit is a non-VCL NAL unit, the value of         TemporalId is equal to the minimum value of the TemporalId         values of all AUs to which the non-VCL NAL unit applies. When         nal_unit_type is equal to PPS NUT, PREFIX APS NUT, or SUFFIX APS         NUT, TemporalId may be greater than or equal to the TemporalId         of the containing AU, as all PPSs and APSs may be included in         the beginning of the bitstream (e.g., when they are transported         out-of-band, and the receiver places them at the beginning of         the bitstream), wherein the first coded picture has TemporalId         equal to 0.         nal_unit_type specifies the NAL unit type, i.e., the type of RB         SP data structure contained in the NAL unit as specified in         Table 2.         NAL units that have nal_unit_type in the range of UNSPEC28 . . .         UNSPEC31, inclusive, for which semantics are not specified,         shall not affect the decoding process specified in this         Specification.         NOTE—NAL unit types in the range of UNSPEC28 . . . UNSPEC31 may         be used as determined by the application. No decoding process         for these values of nal_unit_type is specified in this         Specification. Since different applications might use these NAL         unit types for different purposes, particular care must be         exercised in the design of encoders that generate NAL units with         these nal_unit_type values, and in the design of decoders that         interpret the content of NAL units with these nal_unit_type         values. This Specification does not define any management for         these values. These nal_unit_type values might only be suitable         for use in contexts in which “collisions” of usage (i.e.,         different definitions of the meaning of the NAL unit content for         the same nal_unit_type value) are unimportant, or not possible,         or are managed—e.g., defined or managed in the controlling         application or transport specification, or by controlling the         environment in which bitstreams are distributed.         For purposes other than determining the amount of data in the         decoding units of the bitstream, decoders shall ignore (remove         from the bitstream and discard) the contents of all NAL units         that use reserved values of nal_unit_type.         NOTE—This requirement allows future definition of compatible         extensions to this Specification.

TABLE 2 NAL unit type codes and NAL unit type classes Name of Content of NAL unit and RBSP syntax NAL unit nal_unit_type nal_unit_type structure type class 0 TRAIL_NUT Coded slice of a trailing picture VCL slice_layer_rbsp( ) 1 STSA_NUT Coded slice of an STSA picture VCL slice_layer_rbsp( ) 2 RADL_NUT Coded slice of a RADL picture VCL slice_layer_rbsp( ) 3 RASL_NUT Coded slice of a RASL picture VCL slice_layer_rbsp( ) 4 . . . 6 RSV_VCL_4 . . . Reserved non-IRAP VCL NAL unit VCL RSV_VCL_6 types 7 IDR_W_RADL Coded slice of an IDR picture VCL 8 IDR_N_LP slice_layer_rbsp( ) 9 CRA_NUT Coded slice of a CRA picture VCL silce_layer_rbsp( ) 10 GDR_NUT Coded slice of a GDR picture VCL slice_layer_rbsp( ) 11 RSV_IRAP_11 Reserved IRAP VCL NAL unit types VCL 12 RSV_IRAP_12 13 DCI_NUT Decoding capability information non-VCL decoding_capability_information_rbsp( ) 14 VPS_NUT Video parameter set non-VCL video_parameter_set_rbsp( ) 15 SPS_NUT Sequence parameter set non-VCL seq_parameter_set_rbsp( ) 16 PPS_NUT Picture parameter set non-VCL pic_parameter_set_rbsp( ) 17 PREFIX_APS_NUT Adaptation parameter set non-VCL 18 SUFFIX_APS_NUT adaptation_parameter_set_rbsp( ) 19 PH_NUT Picture header non-VCL picture_header_rbsp( ) 20 AUD_NUT AU delimiter non-VCL access_unit_delimiter_rbsp( ) 21 EOS_NUT End of sequence non-VCL end_of_seq_rbsp( ) 22 EOB_NUT End of bitstream non-VCL end_of_bitstream_rbsp( ) 23 PREFIX_SEI_NUT Supplemental enhancement information non-VCL 24 SUFFIX_SEI_NUT sei_rbsp( ) 25 FD_NUT Filler data non-VCL filler_data_rbsp( ) 26 RSV_NVCL_26 Reserved non-VCL NAL unit types non-VCL 27 RSV_NVCL_27 28 . . . 31 UNSPEC_28 . . . Unspecified non-VCL NAL unit types non-VCL UNSPEC_31 NOTE A clean random access (CRA) picture may have associated RASL or RADL pictures present in the bitstream. NOTE An instantaneous decoding refresh (IDR) picture having nal_unit_type equal to IDR_N_LP does not have associated leading pictures present in the bitstream. An IDR picture having nal_unit_type equal to IDR_W_RADL does not have associated RASL pictures present in the bitstream, but mayu have associated RADL pictures in the bitstream.

For VCL NAL units of any particular picture, the following applies:

-   -   If mixed_nalu_types_in_pic_flag is equal to 0, the value of         nal_unit_type shall be the same for all coded slice NAL units of         a picture. A picture or a PU is referred to as having the same         NAL unit type as the coded slice NAL units of the picture or PU.     -   Otherwise (mixed_nalu_types_in_pic_flag is equal to 1), the VCL         NAL units of one or more subpicturcs of the picture all have a         particular value of nal_unit_type equal to STSA_NUT, RADL_NUT,         RASL_NUT, IDR_W_RADL, IDR_N_LP, or CRA_N LIT, while the other         VCL NAL units in the picture all have a different particular         value of nal_unit_type equal to TRAIL_NUT, RADL_NUT, or         RASL_NUT.

For a single-layer bitstream, the following constraints apply:

-   -   Each picture, other than the first picture in the bitstream in         decoding order, is considered to be associated with the previous         IRAP picture in decoding order.     -   When a picture is a leading picture of an TRAP picture, it shall         be a RADL or RASL picture.     -   When a picture is a trailing picture of an IRAP picture, it         shall not be a RADL or RASL picture.     -   No RASL pictures shall be present in the bitstream that are         associated with an IDR picture.     -   No RADL pictures shall be present in the bitstream that are         associated with an IDR picture having nal_unit_type equal to         IDR_N_LP.     -   NOTE—It is possible to perform random access at the position of         an IRAP PU by discarding all PUs before the IRAP PU (and to         correctly decode the TRAP picture and all the subsequent         non-RASL pictures in decoding order), provided each parameter         set is available (either in the bitstream or by external means         not specified in this Specification) when it is referenced.     -   Any picture that precedes an TRAP picture in decoding order         shall precede the TRAP picture in output order and shall precede         any RADL picture associated with the IRAP picture in output         order.     -   Any RASL picture associated with a CRA picture shall precede any         RADL picture associated with the CRA picture in output order.     -   Any RASL picture associated with a CRA picture shall follow, in         output order, any TRAP picture that precedes the CRA picture in         decoding order.     -   If field_seq_flag is equal to 0 and the current picture is a         leading picture associated with an IRAP picture, it shall         precede, in decoding order, all non-leading pictures that are         associated with the same IRAP picture. Otherwise, let picA and         picB be the first and the last leading pictures, in decoding         order, associated with an IRAP picture, respectively, there         shall be at most one non-leading picture preceding picA in         decoding order, and there shall be no non-leading picture         between picA and picB in decoding order.

It should be noted that generally, an Intra Random Access Point (IRAP) picture is a picture that does not refer to any pictures other than itself for prediction in its decoding process. In JVET-Q2001, an IRAP picture may be a clean random access (CRA) picture or an instantaneous decoder refresh (IDR) picture. In JVET-Q2001, the first picture in the bitstream in decoding order must be an IRAP or a gradual decoding refresh (GDR) picture. JVET-Q2001 describes the concept of a leading picture, which is a picture that precedes the associated IRAP picture in output order. JVET-Q2001 further describes the concept of a trailing picture which is a non-IRAP picture that follows the associated IRAP picture in output order. Trailing pictures associated with an IRAP picture also follow the IRAP picture in decoding order. For IDR pictures, there are no trailing pictures that require reference to a picture decoded prior to the IDR picture. JVET-Q2001 provides where a CRA picture may have leading pictures that follow the CRA picture in decoding order and contain inter picture prediction references to pictures decoded prior to the CRA picture. Thus, when the CRA picture is used as a random access point these leading pictures may not be decodable and are identified as random access skipped leading (RASL) pictures. The other type of picture that can follow an IRAP picture in decoding order and precede it in output order is the random access decodable leading (RADL) picture, which cannot contain references to any pictures that precede the IRAP picture in decoding order. A GDR picture, is a picture for which each VCL NAL unit has nal_unit_type equal to GDR NUT. If the current picture is a GDR picture that is associated with a picture header which signals a syntax element receovery_poc_cnt and there is a picture picA that follows the current GDR picture in decoding order in the CLVS and that has PicOrderCntVal equal to the PicOrderCntVal of the current GDR picture plus the value of recovery_poc_cnt, the picture picA is referred to as the recovery point picture.

As provided in Table 2, a NAL unit may include a sequence parameter set syntax structure. Table 3 illustrates the sequence parameter set syntax structure as provided in JVET-Q2001.

TABLE 3 De- scrip- tor seq_parameter_set_rbsp( ) {  sps_seq_parameter_set_id u(4)  sps_video_parameter_set_id u(4)  sps_max_sublayers_minus1 u(3)  sps_reserved_zero_4bits u(4)  sps_ptl_dpb_hrd_params_present_flag u(1)  if( sps_ptl_dpb_hrd_params_present_flag )   profile_tier_level( 1, sps max_sublayers_minus1 )  gdr_enabled_flag u(1)  chroma_format_idc u(2)  if( chroma_format_idc = = 3 )   separate_colour_plane_flag u(1)  res_change_in_clvs_allowed_flag u(1)  pic_width_max_in_luma_samples ue(v)  pic_height_max_in_luma_samples ue(v)  sps_conformance_window_flag u(1)  if( sps_conformance_window_flag ) {   sps_conf_win_left_offset ue(v)   sps_conf_win_right_offset ue(v)   sps_conf_win_top_offset ue(v)   sps_conf_win_bottom_offset ue(v)  }  sps_log2_ctu_size_minus5 u(2)  subpic_info_present_flag u(1)  if( subpic_info_present_flag ) {   sps_num_subpics_minus1 ue(v)   sps_independent_subpics_flag u(1)   for( i = 0; sps_num_subpics_minus1 > 0 && i <=   sps_num_subpics_minus1; i++ ) {    if( i > 0 && pic_width_max_in_luma_samples >    CtbSizeY )     subpic_ctu_top_left_x[ i ] u(v)    if( i > 0 && pic_height_max_in_luma_samples >    CtbSizeY ) {     subpic_ctu_top_left_y[ i ] u(v)    if( i < sps_num_subpics_minus1 &&      pic_width_max_in_luma_samples > CtbSizeY )     subpic_width_minus1[ i ] u(v)    if( i < sps_num_subpics_minus1 &&      pic_height_max_in_luma_samples > CtbSizeY )     subpic_height_minus1[ i ] u(v)    if( !sps_independent_subpics_flag) {     subpic_treated_as_pic_flag[ i ] u(1)     loop_filter_across_subpic_enabled_flag[ i ] u(1)    }   }   sps_subpic_id_len_minus1 ue(v)   subpic_id_mapping_explicitly_signalled_flag u(1)   if( subpic_id_mapping_explicitly_signalled_flag ) {    subpic_id_mapping_in_sps_flag u(1)    if( subpic_id_mapping_in_sps_flag )     for( i = 0; i <= sps_num_subpics_minus1; i++ )      sps_subpic_id[ i ] u(v)   }  }  bit_depth_minus8 ue(v)  sps_entropy_coding_sync_enabled_flag u(1)  if( sps_entropy_coding_sync_enabled_flag )   sps_wpp_entry_point_offsets_present_flag u(1)  sps_weighted_pred_flag u(1)  sps_weighted_bipred_flag u(1)  log2_max_pic_order_cnt_lsb_minus4 u(4)  sps_poc_msb_flag u(1)  if( sps_poc_msb_flag )   poc_msb_len_minus1 ue(v)  num_extra_ph_bits_bytes u(2)   extra_ph_bits_struct( num_extra_ph_bits_bytes )  num_extra_sh_bits_bytes u(2)   extra_sh_bits_struct( num_extra_sh_bits_bytes )  if( sps_max_sublayers_minus1 > 0 )   sps_sublayer_dpb_params_flag u(1)  if( sps_ptl_dpb_hrd_params_present_flag )   dpb_parameters( sps_max_sublayers_minus1,   sps_sublayer_dpb_params_flag )  long_term_ref_pics_flag u(1)  inter_layer_ref_pics_present_flag u(1)  sps_idr_rpl_present_flag u(1)  rpl1_same_as_rpl0_flag u(1)  for( i = 0; i < !rpl1_same_as_rpl0_flag ? 2 : 1; i++ ) {   num_ref_pic_lists_in_sps[ i ] ue(v)   for( j = 0; j < num_ref_pic_lists_in_sps[ i ]; j++)    ref_pic_list_struct( i, j )  }  if( ChromaArrayType != 0 )   qtbtt_dual_tree_intra_flag u(1)  log2_min_luma_coding_block_size_minus2 ue(v)  partition_constraints_override_enabled_flag u(1)  sps_log2_diff_min_qt_min_cb_intra_slice_luma ue(v)  sps_max_mtt_hierarchy_depth_intra_slice_luma ue(v)  if( sps_max_mtt_hierarchy_depth_intra_slice_luma != 0 ) {   sps_log2_diff_max_bt_min_qt_intra_slice_luma ue(v)   sps_log2_diff_max_tt_min_qt_intra_slice_luma ue(v)  }  sps_log2_diff_min_qt_min_cb_inter_slice ue(v)  sps_max_mtt_hierarchy_depth_inter_slice ue(v)  if( sps_max_mtt_hierarchy_depth_inter_slice != 0 ) {   sps_log2_diff_max_bt_min_qt_inter_slice ue(v)   sps_log2_diff_max_tt_min_qt_inter_slice ue(v)  }  if( qtbtt_dual_tree_intra_flag ) {   sps_log2_diff_min_qt_min_cb_intra_slice_chroma ue(v)   sps_max_mtt_hierarchy_depth_intra_slice_chroma ue(v)   if( sps_max_mtt_hierarchy_depth_intra_slice_chroma   != 0 ) {    sps_log2_diff_max_bt_min_qt_intra_slice_chroma ue(v)    sps_log2_diff_max_tt_min_qt_intra_slice_chroma ue(v)   }  }  sps_max_luma_transform_size_64_flag u(1)  if( ChromaArrayType != 0 ) {   sps_joint_cbcr_enabled_flag u(1)   same_qp_table_for_chroma u(1)   numQpTables = same_qp_table_for_chroma ? 1 : (   sps_joint_cbcr_enabled_flag ? 3 : 2 )   for( i = 0; i < numQpTables; i++ ) {    qp_table_start_minus26[ i ] se(v)    num_points_in_qp_table_minus1[ i ] ue(v)    for( j = 0; j <= num_points_in_qp_table_minus1[ i ];    j++ ) {     delta_qp_in_val_minus1[ i ][ j ] ue(v)     delta_qp_diff_val[ i ][ j ] ue(v)    }   }  }  sps_sao_enabled_flag u(1)  sps_alf_enabled_flag u(1)  if( sps_alf_enabled_flag && ChromaArrayType != 0 )   sps_ccalf_enabled_flag u(1)  sps_transform_skip_enabled_flag u(1)  if( sps_transform_skip_enabled_flag ) {   log2_transform_skip_max_size_minus2 ue(v)   sps_bdpcm_enabled_flag u(1)  }  sps_ref_wraparound_enabled_flag u(1)  sps_temporal_mvp_enabled_flag u(1)  if( sps_temporal_mvp_enabled_flag )   sps_sbtmvp_enabled_flag u(1)  sps_amvr_enabled_flag u(1)  sps_bdof_enabled_flag u(1)  if( sps_bdof_enabled_flag )   sps_bdof_pic_present_flag u(1)  sps_smvd_enabled_flag u(1)  sps_dmvr_enabled_flag u(1)  if( sps_dmvr_enabled_flag)   sps_dmvr_pic_present_flag u(1)  sps_mmvd_enabled_flag u(1)  sps_isp_enabled_flag u(1)  sps_mrl_enabled_flag u(1)  sps_mip_enabled_flag u(1)  if( ChromaArrayType != 0 )   sps_cclm_enabled_flag u(1)  if( chroma_format_idc = = 1 ) {   sps_chroma_horizontal_collocated_flag u(1)   sps_chroma_vertical_collocated_flag u(1)  }  sps_mts_enabled_flag u(1)  if( sps_mts_enabled_flag ) {   sps_explicit_mts_intra_enabled_flag u(1)   sps_explicit_mts_inter_enabled_flag u(1)  }  six_minus_max_num_merge_cand ue(v)  sps_sbt_enabled_flag u(1)  sps_affine_enabled_flag u(1)  if( sps_affine_enabled_flag ) {   five_minus_max_num_subblock_merge_cand ue(v)   sps_affine_type_flag u(1)   if( sps_amvr_enabled_flag )    sps_affine_amvr_enabled_flag u(1)   sps_affine_prof_enabled_flag u(1)   if( sps_affine_prof_enabled_flag )    sps_prof_pic_present_flag u(1)  }  sps_palette_enabled_flag u(1)  if( ChromaArrayType = = 3 &&  !sps_max_luma_transform_size_64_flag )   sps_act_enabled_flag u(1)  if( sps_transform_skip_enabled_flag | |  sps_palette_enabled_flag )   min_qp_prime_ts_minus4 ue(v)  sps_bcw_enabled_flag u(1)  sps_ibc_enabled_flag u(1)  if( sps_ibc_enabled_flag )   six_minus_max_num_ibc_merge_cand ue(v)  sps_ciip_enabled_flag u(1)  if( sps_mmvd_enabled_flag )   sps_fpel_mmvd_enabled_flag u(1)  if( MaxNumMergeCand >= 2 ) {   sps_gpm_enabled_flag u(1)   if( sps_gpm_enabled_flag && MaxNumMergeCand >= 3 )    max_num_merge_cand_minus_max_num_gpm_cand ue(v)  }  sps_lmcs_enabled_flag u(1)  sps_lfnst_enabled_flag u(1)  sps_ladf_enabled_flag u(1)  if( sps_ladf_enabled_flag ) {   sps_num_ladf_intervals_minus2 u(2)   sps_ladf_lowest_interval_qp_offset se(v)   for( i = 0; i < sps_num_ladf_intervals_minus2 + 1; i++ ) {    sps_ladf_qp_offset[ i ] se(v)    sps_ladf_delta_threshold_minus1[ i ] ue(v)   }  }  log2_parallel_merge_level_minus2 ue(v)  sps_scaling_list_enabled_flag u(1)  sps_dep_quant_enabled_flag u(1)  if( !sps_dep_quant_enabled_flag )   sps_sign_data_hiding_enabled_flag u(1)  sps_virtual_boundaries_enabled_flag u(1)  if( sps_virtual_boundaries_enabled_flag ) {   sps_virtual_boundaries_present_flag u(1)   if( sps_virtual_boundaries_present_flag ) {    sps_num_ver_virtual_boundaries u(2)    for( i = 0; i < sps_num_ver_virtual_boundaries; i++ )     sps_virtual_boundaries_pos_x[ i ] u(13)    sps_num_hor_virtual_boundaries u(2)    for( i = 0; i < sps_num_hor_virtual_boundaries; i++ )     sps_virtual_boundaries_pos_y[ i ] u(13)   }  }  if( sps_ptl_dpb_hrd_params_present_flag ) {   sps_general_hrd_params_present_flag u(1)   if( sps_general_hrd_params_present_flag ) {    general_hrd_parameters( )    if( sps_max_sublayers_minus1 > 0 )     sps_sublayer_cpb_params_present_flag u(1)    firstSubLayer = sps_sublayer_cpb_params_present_flag    ? 0 :      sps_max_sublayers_minus1    ols_hrd_parameters( firstSubLayer,    sps_max_sublayers_minus1 )   }  }  field_seq_flag u(1)  vui_parameters_present_flag u(1)  if( vui_parameters_present_flag )   vui_parameters( ) /* Specified in ITU-T H.SEI | ISO/IEC   23002-7 */  sps_extension_flag u(1)  if( sps_extension_flag )   while( more_rbsp_data( ) )    sps_extension_data_flag u(1)  rbsp_trailing_bits( ) }

With respect to Table 3, JVET-Q2001 provides the following semantics:

An SPS RBSP shall be available to the decoding process prior to it being referenced, included in at least one AU with Temporand equal to 0 or provided through external means.

All SPS NAL units with a particular value of sps_seq_parameter_set_id in a CVS shall have the same content.

sps_seq_parameter_set_id provides an identifier for the SPS for reference by other syntax elements.

SPS NAL units, regardless of the nuh_layer_id values, share the same value space of sps_seq_parameter_set_id.

Let spsLayerId be the value of the nuh_layer_id of a particular SPS NAL unit, and vclLayerId be the value of the nuh_layer_id of a particular VCL NAL unit. The particular VCL NAL unit shall not refer to the particular SPS NAL unit unless spsLayerId is less than or equal to vclLayerId and the layer with nuh_layer_id equal to spsLayerId is included in at least one OLS that includes the layer with nuh_layer_id equal to vclLayerId.

sps_video_parameter_set_id, when greater than 0, specifies the value of vps_video_parameter_set_id for the VPS referred to by the SPS.

When sps_video_parameter_set_id is equal to 0, the following applies:

-   -   The SPS does not refer to a VPS.     -   No VPS is referred to when decoding each CLVS referring to the         SPS.     -   The value of vps_max_layers_minus1 is inferred to be equal to 0.     -   The CVS shall contain only one layer (i.e., all VCL NAL unit in         the CVS shall have the same value of nuh_layer_id).     -   The value of GeneralLayerIdx[nuh_layer_id] is inferred to be         equal to 0.     -   The value of         vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id] ] is         inferred to be equal to 1.

When vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is equal to 1, the SPS referred to by a CLVS with a particular nuh_layer_id value nuhLayerId shall have nuh_layer_id equal to nuhLayerId.

The value of sps_video_parameter_set_id shall be the same in all SPSs that are referred to by CLVSs in a CVS.

sps_max_sublayers_minus1 plus 1 specifies the maximum number of temporal sublayers that may be present in each CLVS referring to the SPS. The value of sps_max_sublayers_minus1 shall be in the range of 0 to vps_max_sublayers_minus1, inclusive. sps_reserved_zero_4 bits shall be equal to 0 in bitstreams conforming to this version of this Specification. Other values for sps_reserved_zero_4bits are reserved for future use by ITU-T|ISO/IEC. sps_ptl_dpb_hrd_params_present_flag equal to 1 specifies that a profile_tier_level( ) syntax structure and a dpb_parameters( ) syntax structure are present in the SPS, and a general_hrd_parameters( ) syntax structure and an ols_hrd_parameters( ) syntax structure may also be present in the SPS. sps_ptl_dpb_hrd_params_present_flag equal to 0 specifies that none of these four syntax structures is present in the SPS. The value of sps_ptl_dpb_hrd_params_present_flag shall be equal to vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]]. gdr_enabled_flag equal to 1 specifies that GDR pictures may be present in CLVSs referring to the SPS. gdr_enabled_flag equal to 0 specifies that GDR pictures are not present in CLVSs referring to the SPS. chroma_format_idc specifies the chroma sampling relative to the luma sampling as specified. separate_colour_planc_flag equal to 1 specifies that the three colour components of the 4:4:4 chroma format are coded separately. separate_colour_plane_flag equal to 0 specifies that the colour components are not coded separately. When separate_colour_plane_flag is not present, it is inferred to be equal to 0. When separate_colour_plane_flag is equal to 1, the coded picture consists of three separate components, each of which consists of coded samples of one colour plane (Y, Cb, or Cr) and uses the monochrome coding syntax. In this case, each colour plane is associated with a specific colour_plane_id value.

NOTE—There is no dependency in decoding processes between the colour planes having different colour_plane_id values. For example, the decoding process of a monochrome picture with one value of colour_plane_id does not use any data from monochrome pictures having different values of colour_plane_id for inter prediction. Depending on the value of separate_colour_plane_flag, the value of the variable ChromaArrayType is assigned as follows:

-   -   If separate_colour_plane_flag is equal to 0, ChromaArrayType is         set equal to chroma_format_idc.     -   Otherwise (separate_colour_plane_flag is equal to 1),         ChromaArrayType is set equal to 0.         res_change_in_clvs_allowed_flag equal to 1 specifies that the         picture spatial resolution may change within a CLVS referring to         the SPS. res_change_in_clvs_allowed_flag equal to 0 specifies         that the picture spatial resolution does not change within any         CLVS referring to the SPS.         pic_width_max_in_luma_samples specifies the maximum width, in         units of luma samples, of each decoded picture referring to the         SPS. pic_width_max_in_luma_samples shall not be equal to 0 and         shall be an integer multiple of Max(8, MinCbSizeY).         It is a requirement of bitstream conformance that, for any OLS         with OLS index i that contains one or more layers that refers to         the SPS, the value of pic_width_max_in_luma_samples shall be         less than or equal to the value of ols_dpb_pic_width[i].         pic_height_max_in_luma_samples specifies the maximum height, in         units of luma samples, of each decoded picture referring to the         SPS. pic_height_max_in_luma_samples shall not be equal to 0 and         shall be an integer multiple of Max(8, MinCbSizeY).         It is a requirement of bitstream conformance that, for any OLS         with OLS index i that contains one or more layers that refers to         the SPS, the value of pic_height_max_in_luma_samples shall be         less than or equal to the value of ols_dpb_pic_height[i].         sps_conformance_window_flag equal to 1 indicates that the         conformance cropping window offset parameters follow next in the         SPS. sps_conformance_window_flag equal to 0 indicates that the         conformance cropping window offset parameters are not present in         the SPS.         sps_conf win_left_offset, sps_conf win_tight_offset, sps_conf         win_top_offset, and sps_conf_win_bottom_offset specify the         cropping window that is applied to pictures with         pic_width_in_luma_samples equal to pic_width_maxin_luma_samples         and pic_height_in_luma_samples equal to         pic_height_max_in_luma_samples. When sps_conformance_window_flag         is equal to 0, the values of sps_conf win_left_offset,         sps_conf_win_right_offset, sps_conf win_top_offset, and         sps_conf_win_bottom_offset are inferred to be equal to 0.         The conformance cropping window contains the luma samples with         horizontal picture coordinates from         SubWidthC*sps_conf_win_left_offset to         pic_width_max_in_limia_samples−(Sub         WidthC*sps_conf_win_right_offset+1) and vertical picture         coordinates from SubHeightC*sps_conf_win_top_offset to         pic_height_max_in_luma_samples−(SubHeightC*sps_conf_win_bottom_offset+1),         inclusive.         The value of         SubWidthC*(sps_conf_win_left_offset+sps_conf_win_right_offset)         shall be less than pic_width_max_in_luma_samples, and the value         of         SubHeightC*(sps_conf_win_top_offset+sps_conf_win_bottom_offset)         shall be less than pic_height_max_in_luma_samples.         When ChromaArrayType is not equal to 0, the corresponding         specified samples of the two chroma arrays are the samples         having picture coordinates (x/SubWidthC, y/SubHeightC), where         (x, y) are the picture coordinates of the specified luma         samples.         NOTE—The conformance cropping window offset parameters are only         applied at the output. All internal decoding processes are         applied to the uncropped picture size.         sps_log 2_ctu_size_minus5 plus 5 specifies the luma coding tree         block size of each CTU. The value of sps_log 2_ctu_size_minus5         shall be in the range of 0 to 2, inclusive. The value 3 for         sps_log 2_ctu_size_minus5 is reserved for future use by ITU-T         ISO/IEC.         The variables CtbLog 2SizeY and CtbSizeY are derived as follows:         CtbLog 2SizeY=sps_log 2_ctu_size_minus5+5

CtbSizeY=1<<CtbLog 2SizeY

subpic_info_present_flag equal to 1 specifies that subpicture information is present for the CLVS and there may be one or more than one subpicture in each picture of the CLVS. subpic_info_present_flag equal to 0 specifies that subpicture information is not present for the CLVS and there is only one subpicture in each picture of the CLVS. When res_change_in_clvs_allowed_flag is equal to 1, the value of subpic_info_present_flag shall be equal to 0. NOTE—When a bitstream is the result of a sub-bitstream extraction process and contains only a subset of the subpictures of the input bitstream to the sub-bitstream extraction process, it might be required to set the value of subpic_info_present_flag equal to 1 in the RBSP of the SPSs. sps_num_subpics_minus1 plus 1 specifies the number of subpictures in each picture in the CLVS. The value of sps num subpics minus1 shall be in the range of 0 to Ceil(pic width max in luma samples+CtbSizeY)*Ceil(pic_height_max_in_luma_samples+CtbSizeY)−1, inclusive. When not present, the value of sps_num_subpics_minus1 is inferred to be equal to 0. sps_independent_subpics_flag equal to 1 specifies that no intra prediction, no inter prediction and no in-loop filtering operations may be performed across any subpicture boundary in the CLVS. sps_independent_subpics_flag equal to 0 specifies that inter prediction or in-loop filtering operations across the subpicture boundaries in the CLVS may be allowed. When not present, the value of sps_independent_subpics_flag is inferred to be equal to 0. subpic_ctu_top_left_x[i] specifies horizontal position of top left CTU of i-th subpicture in unit of CtbSizeY. The length of the syntax element is Ceil(Log 2((pic_width_max_in_luma_samples+CtbSizeY−1)>>CtbLog 2SizeY)) bits. When not present, the value of subpic_ctu_top_left_x[i] is inferred to be equal to 0. subpic_ctu_top_left_y[i] specifies vertical position of top left CTU of i-th subpicture in unit of CtbSizeY. The length of the syntax element is Ceil(Log 2((pic_height_max_in_luma_samples+CtbSizeY−1)>>CtbLog 2SizeY)) bits. When not present, the value of subpic_ctu_top_left_y[i] is inferred to be equal to 0. subpic_width_minus1[i] plus 1 specifies the width of the i-th subpicture in units of CtbSizeY. The length of the syntax element is Ceil(Log 2((pic_width_max_in_luma_samples+CtbSizeY−1)>>CtbLog 2SizeY)) bits. When not present, the value of subpic_width_minus1[i] is inferred to be equal to ((pic width max in luma samples+CtbSizeY−1)>>CtbLog 2SizeY)−subpic_ctu_top_left_x[i]−1. subpic_height_minus1[i] plus 1 specifies the height of the i-th subpicture in units of CtbSizeY. The length of the syntax element is Ceil(Log 2((pic_height_max_in_luma_samples+CtbSizeY−1)>>CtbLog 2SizeY)) bits. When not present, the value of subpic_height_minus1[i] is inferred to be equal to ((pic_height_max_in_luma_samples+CtbSizeY−1)>>CtbLog 2SizeY)−subpic_ctu_top_left_y[i]−1. subpic_treated_as_pic_flag[i] equal to 1 specifies that the i-th subpicture of each coded picture in the CLVS is treated as a picture in the decoding process excluding in-loop filtering operations. subpic_treated_as_pic_flag[i] equal to 0 specifies that the i-th subpicture of each coded picture in the CLVS is not treated as a picture in the decoding process excluding in-loop filtering operations. When not present, the value of subpic_treated_as_pic_flag[i] is inferred to be equal to sps_independent_subpics_flag. When subpic_treated_as_pic_flag[i] is equal to 1, it is a requirement of bitstream conformance that all of the following conditions are true for each output layer and its reference layers in an OLS that includes the layer containing the i-th subpicture as an output layer:

-   -   All pictures in the output layer and its reference layers shall         have the same value of pic_width_in_luma_samples and the same         value of pic_height_in_luma_samples.     -   All the SPSs referred to by the output layer and its reference         layers shall have the same value of sps_num_subpics_minus1 and         shall have the same values of subpic_ctu_top_left_x[j],         subpic_ctu_top_left_y[j], subpic_width_minus1 [j],         subpic_height_minus1[j], and         loop_filter_across_subpic_enabled_flag[j], respectively. for         each value of j in the range of 0 to sps_num_subpics_minus1,         inclusive.     -   All pictures in each access unit in the output layer and its         reference layers shall have the same value of SubpicIdVal[j] for         each value of j in the range of 0 to sps num subpics minus1,         inclusive. loop_filter_across_subpic_enabled_flag[i] equal to 1         specifies that in-loop filtering operations may be performed         across the boundaries of the i-th subpicture in each coded         picture in the CLVS. loop_filter_across_subpic_enabled_flag[i]         equal to 0 specifies that in-loop filtering operations are not         performed across the boundaries of the i-th subpicture in each         coded picture in the CLVS. When not present, the value of         loop_filter_across_subpic_enabled_pic_flag[i] is inferred to be         equal to 1−sps_independent_subpics_flag.         It is a requirement of bitstream conformance that the shapes of         the subpictures shall be such that each subpicture, when         decoded, shall have its entire left boundary and entire top         boundary consisting of picture boundaries or consisting of         boundaries of previously decoded subpictures.         sps_subpic_id_len_minus1 plus 1 specifies the number of bits         used to represent the syntax element sps_subpic_id[i], the         syntax elements pps_subpic_id[i], when present, and the syntax         element slice_subpic_id, when present. The value of         sps_subpic_id_len_minus1 shall be in the range of 0 to 15.         inclusive. The value of 1<<(sps_subpic_id_len_minus1+1) shall be         greater than or equal to sps_num_subpics_minus1+1.         subpic_id_mapping_explictly_signalled_flag equal to 1 specifies         that the subpicture ID mapping is explicitly signalled, either         in the SPS or in the PPSs referred to by coded pictures of the         CLVS. subpic_id_mapping_explicitly_signalled_flag equal to 0         specifies that the subpicture ID mapping is not explicitly         signalled for the CLVS. When not present, the value of         subpic_id_mapping_explicitly_signalled_flag is inferred to be         subpic_id_mapping_in_sps_flag equal to 1 specifies that the         subpicture ID mapping is signalled in the SPS when         subpic_id_mapping_explicitly_signalled_flag is equal to 1.         subpic_id_mapping_in_sps_flag equal to 0 specifies that         subpicture ID mapping is signalled in the PPSs referred to by         coded pictures of the CLVS when         subpic_id_mapping_explicitly_signalled_flag is equal to 1.         sps_subpic_id[i] specifies the subpicture TD of the i-th         subpicture. The length of the sps_subpic_id[i] syntax element is         sps_subpic_id_len_minus1+1 bits.         bit_depth_minus8 specifies the bit depth of the samples of the         luma and chroma arrays, BitDepth, and the value of the luma and         chroma quantization parameter range offset, QpBdOffset, as         follows:

BitDepth=8+bit_depth_minus8 QpBdOffset=6*bit_depth_minus8

bit_depth_minus8 shall be in the range of 0 to 8, inclusive. sps_entropy_coding_sync_enabled_flag equal to 1 specifies that a specific synchronization process for context variables is invoked before decoding the CTU that includes the first CTB of a row of CTBs in each tile in each picture referring to the SPS, and a specific storage process for context variables is invoked after decoding the CTU that includes the first CTB of a row of CTBs in each tile in each picture referring to the SPS. sps_entropy_coding_sync_enabled_flag equal to 0 specifies that no specific synchronization process for context variables is required to be invoked before decoding the CTU that includes the first CTB of a row of CTBs in each tile in each picture referring to the SPS, and no specific storage process for context variables is required to be invoked after decoding the CTU that includes the first CTB of a row of CTBs in each tile in each picture referring to the SPS. sps_wpp_entry_point_offsets_present_flag equal to 1 specifies that signalling for entry point offsets for CTU rows may be present in the slice headers of pictures referring to the SPS when sps_entropy_coding_sync_enabled_flag is equal to 1. sps_wpp_entry_point_offsets_present_flag equal to 0 specifies that signalling for entry point offsets for CTU rows are not present in the slice headers of pictures referring to the SPS. When not present, the value of sps_wpp_entry_point_offsets_present_flag is inferred to be equal to 0. sps_weighted_pred_flag equal to 1 specifies that weighted prediction may be applied to P slices referring to the SPS. sps_weighted_pred_flag equal to 0 specifies that weighted prediction is not applied to P slices referring to the SPS. sps_weighted_bipred_flag equal to 1 specifics that explicit weighted prediction may be applied to B slices referring to the SPS. sps_weighted_bipred_flag equal to 0 specifies that explicit weighted prediction is not applied to B slices referring to the SPS.

log 2_max_pic_ordercnt_lsb_minus4 specifies the value of the variable MaxPicOrderCntLsb that is used in the decoding process for picture order count as follows:

MaxPicOrderCntLsb=2^((log) 2_max_pic_order_cnt_lsb_minus4+4) The value of log 2 max_pic_order_cnt_lsb_minus4 shall be in the range of 0 to 12, inclusive. sps_poc_msb_flag equal to 1 specifies that the ph_poc_msb_present_flag syntax element is present in PHs referring to the SPS. sps_poc_msb_flag equal to 0 specifies that the ph_poc_msb_present_flag syntax element is not present in PHs referring to the SPS. poc_msb_len_minus1 plus 1 specifies the length, in bits, of the poc_msb_val syntax elements, when present in the PHs referring to the SPS. The value of poc_msb_len_minus1 shall be in the range of 0 to 32-log 2_max_pic_order_cnt_lsb_minus4-5, inclusive. num_extra_ph_bits_bytes specifies the number of bytes of extra bits in the PH syntax structure for coded pictures referring to the SPS. The value of num_extra_ph_bits_bytes shall be equal to 0 in bitstreams conforming to this version of this Specification. Although the value of num_extra_ph_bits_bytes is required to be equal to 0 in this version of this Specification, decoder conforming to this version of this Specification shall allow the value of num_extra_ph_bits_bytes equal to 1 or 2 to appear in the syntax. num_extra_sh_bits_bytes specifies the number of bytes of extra bits in the slice headers for coded pictures referring to the SPS. The value of num_extra_sh_bits_bytes shall be equal to 0 in bitstreams conforming to this version of this Specification. Although the value of num_extra_sh_bits_bytes is required to be equal to 0 in this version of this Specification, decoder conforming to this version of this Specification shall allow the value of num_extra_sh_bits_bytes equal to 1 or 2 to appear in the syntax. sps_sublayer_dpb_params_flag is used to control the presence of max_dec_pic_buffering_minus1 [i], max_num_reorder_pics[i], and max_latency_increase_plus1[i] syntax elements in the dpb_parameters( ) syntax structure in the SPS. When not present, the value of sps_sub_dpb_params_info_present_flag is inferred to be equal to 0. long_term_ref_pics_flag equal to 0 specifies that no LTRP is used for inter prediction of any coded picture in the CLVS. long_term_ref_pics_flag equal to 1 specifies that LTRPs may be used for inter prediction of one or more coded pictures in the CLVS. inter_layer_ref_pics_present_flag equal to 0 specifies that no ILRP is used for inter prediction of any coded picture in the CLVS. inter_layer_ref_pic_flag equal to 1 specifies that ILRPs may be used for inter prediction of one or more coded pictures in the CLVS. When sps_video_parameter_set_id is equal to 0, the value of inter layer ref_pics_present_flag is inferred to be equal to 0. When vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id] ] is equal to 1, the value of inter_layer_ref_pics_present_flag shall be equal to 0. sps_idr_rpl_present_flag equal to 1 specifies that reference picture list syntax elements are present in slice headers of IDR pictures. sps_idr_rpl_present_flag equal to 0 specifies that reference picture list syntax elements are not present in slice headers of IDR pictures.

rpl1_same_as_rpl0_flag equal to 1 specifies that the syntax element num_ref_pic_lists_in_sps[1] and the syntax structure ref_pic_list_struct(1, rplsIdx) are not present and the following applies:

-   -   The value of num_ref_pic_lists_in_sps[1] is inferred to be equal         to the value of num ref pic lists in sps[0].     -   The value of each of syntax elements in ref_pic_list_struct(1,         rplsIdx) is inferred to be equal to the value of corresponding         syntax element in ref_pic_list_struct(0, rplsIdx) for rplsIdx         ranging from 0 to num ref pic lists in sps[0]−1.         num_ref_pic_lists_in_sps[i] specifies the number of the         ref_pic_list_struct(listIdx, rplsIdx) syntax structures with         listIdx equal to i included in the SPS. The value of         num_ref_pic_lists_in_sps[i] shall be in the range of 0 to 64.         inclusive.         NOTE—For each value of listIdx (equal to 0 or 1), a decoder         should allocate memory for a total number of         num_ref_pic_lists_in_sps[i]+1 ref_pic_list_struct(listIdx,         rplsIdx) syntax structures since there may be one         ref_pic_list_struct(listIdx, rplsIdx) syntax structure directly         signalled in the slice headers of a current picture.         qtbtt_dual_tree_intra_flag equal to 1 specifies that, for I         slices, each CTU is split into coding units with 64×64 luma         samples using an implicit quadtree split, and these coding units         are the root of two separate coding_tree syntax structure for         luma and chroma. qtbtt_dual_tree_intra_flag equal to 0 specifies         separate coding_tree syntax structure is not used for 1 slices.         When qtbtt_dual_tree_intra_flag is not present, it is inferred         to be equal to 0.         log 2_min_luma_coding_block_size_minus2 plus 2 specifies the         minimum luma coding block size. The value range of log         2_min_luma_coding_block_size_minus2 shall be in the range of 0         to Min(4, sps_log 2_ctu_size_minus5+3), inclusive.         The variables MinCbLog 2SizeY, MinCbSizeY, IbcBufWidthY,         IbcBufWidthC and Vsize are derived as follows:         MinCbLog 2SizeY=log 2 min luma coding block size minus2+2

MinCbSizeY=1<<MinCbLog 2SizeY IbcBufWidthY=256*128/CtbSizeY IbcBufWidthC=IbcBufWidthY/SubWidthC VSize=Min(64, CtbSizeY)

The value of MinCbSizeY shall less than or equal to VSize. The variables CtbWidthC and CtbHeightC, which specify the width and height, respectively, of the array for each chroma CTB, are derived as follows:

-   -   If chroma_format_idc is equal to 0 (monochrome) or         separate_colour_plane_flag is equal to 1, CtbWidthC and         CtbHeightC are both equal to 0.     -   Otherwise, CtbWidthC and CtbHeightC are derived as follows:

CtbWidthC=CtbSizeY/SubWidthC CtbHeightC=CtbSizeY/SubHeightC

For log 2BlockWidth ranging from 0 to 4 and for log 2BlockHeight ranging from 0 to 4, inclusive, the up-right diagonal scan order array initialization process as specified is invoked with 1<<log 2BlockWidth and 1<<log 2BlockHeight as inputs, and the output is assigned to DiagScanOrder[log 2BlockWidth][log 2BlockHeight]. For log 2BlockWidth ranging from 0 to 6 and for log 2BlockHeight ranging from 0 to 6, inclusive, the horizontal and vertical traverse scan order array initialization process as specified is invoked with 1<<log 2BlockWidth and 1<<log 2BlockHeight as inputs, and the output is assigned to

HorTravScanOrder[log 2BlockWidth][log 2BlockHeight] and VerTravScanOrder[log 2BlockWidth][log 2BlockHeight].

partition_constraints_override_enabled_flag equal to 1 specifies the presence of partition_constraints_override_flag in PHs referring to the SPS. partition_constraints_override_enabled_flag equal to 0 specifies the absence of partition_constraints_override_flag in PT-Ts referring to the SPS. sps_log 2_diff_min_qt_min_cb_intra_slice_luma specifies the default difference between the base 2 logarithm of the minimum size in tuna samples of a luma leaf block resulting from quadtree splitting of a CTU and the base 2 logarithm of the minimum coding block size in luma samples for luma CUs in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log 2_diff_min_qt_min_cb_luma present in PHs referring to the SPS. The value of sps_log 2_diff_min_qt_min_cb_intra_slice_luma shall be in the range of 0 to CtbLog 2SizeY−MinCbLog 2SizeY, inclusive. The base 2 logarithm of the minimum size in luma samples of a luma leaf block resulting from quadtree splitting of a CTU is derived as follows: MinQtLog 2SizeIntraY=sps_log 2_diff_min_qt_min_cb_intra_slice_luma+MinCbLog 2SizeY sps_max_mtt_hierarchy_depth_intra_slice_luma specifies the default maximum hierarchy depth for coding units resulting from multi-type tree splitting of a quadtree leaf in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default maximum hierarchy depth can be overridden by ph_max_mtt_hierarchy_depth_intra_slice_luma present in PHs referring to the SPS. The value of sps_max_mtt_hierarchy_depth_intra_slice_luma shall be in the range of 0 to 2*(CtbLog 2SizeY−MinCbLog 2SizeY), inclusive. sps_log 2_diff max_bt_min_qt_intra_slice_luma specifics the default difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a binary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log 2_diff max_bt_min_qt_luma present in PHs referring to the SPS. The value of sps_log 2_diff max_bt_min_qt_intra_slice_luma shall be in the range of 0 to CtbLog 2SizeY−MinQtLog 2SizeIntraY, inclusive. When sps_log 2_diff_max_bt_min_qt_intra_slice_luma is not present, the value of sps_log 2_diff max_bt_min_qt_intra_slice_luma is inferred to be equal to 0. sps_log 2_diff_max_bt_min_qt_intra_slice_luma specifies the default difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a ternary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log 2_diff_max_tt_min_qt_luma present in PHs referring to the SPS. The value of sps_log 2_diff_max_tt_min_qt_intra_slice_luma shall be in the range of 0 to CtbLog 2SizeY−MinQtLog 2SizeIntraY, inclusive. When sps_log 2_diff_max_tt_min_qt_intra_slice_luma is not present, the value of sps_log 2_diff_max_tt_min_qt_intra_slice_luma is inferred to be equal to 0. sps_log 2_diff_min_qt_min_cb_inter_slice specifies the default difference between the base 2 logarithm of the minimum size in luma samples of a luma leaf block resulting from quadtree splitting of a CTU and the base 2 logarithm of the minimum luma coding block size in luma samples for luma CUs in slices with slice_type equal to 0 (B) or 1 (P) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log 2_diff_min_qt_min_cb_luma present in PHs referring to the SPS. The value of sps_log 2_diff_min_qt_min_cb_inter_slice shall be in the range of 0 to CtbLog 2SizeY−MinCbLog 2SizeY, inclusive. The base 2 logarithm of the minimum size in luma samples of a luma leaf block resulting from quadtree splitting of a CTU is derived as follows: MinQtLog 2SizeInterY=sps_log 2_diff_min_qt_min_cb_inter_slice+MinCbLog 2SizeY sps_max_mtt_hierarchy_depth_inter_slice specifies the default maximum hierarchy depth for coding units resulting from multi-type tree splitting of a quadtree leaf in slices with slice_type equal to 0 (B) or 1 (P) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default maximum hierarchy depth can be overridden by ph_max_mtt_hierarchy_depth_inter_slice present in PHs referring to the SPS. The value of sps_max_mtt_hierarchy_depth_inter_slice shall be in the range of 0 to 2*(CtbLog 2SizeY−MinCbLog 2SizeY), inclusive. sps_log 2_diff max_bt_min_qt_inter_slice specifies the default difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a binary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU in slices with slice_type equal to 0 (B) or 1 (P) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log 2_diff max_bt_min_qt_luma present in PHs referring to the SPS. The value of sps_log 2_diff max_bt_min_qt_inter_slice shall be in the range of 0 to CtbLog 2SizeY−MinQtLog 2SizeInterY, inclusive. When sps_log 2_diff max_bt_min_qt_inter_slice is not present, the value of sps_log 2_diff_max_bt_min_qt_inter_slice is inferred to be equal to 0. sps_log 2_diff_max_tt_min_qt_inter_slice specifies the default difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a ternary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU in slices with slice type equal to 0 (B) or 1 (P) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log 2_diff_max_tt_min_qt_luma present in PHs referring to the SPS. The value of sps_log 2_diff_max_tt_min_qt_inter_slice shall be in the range of 0 to CtbLog 2SizeY−MinQtLog 2SizeInterY, inclusive. When sps_log 2_diff_max_tt_min_qt_inter_slice is not present, the value of sps_log 2_diff_max_tt_min_qt_inter_slice is inferred to be equal to 0. sps_log 2_diff_min_qt_min_cb_intra_slice_chroma specifies the default difference between the base 2 logarithm of the minimum size in luma samples of a chroma leaf block resulting from quadtree splitting of a chroma CTU with treeType equal to DUAL_TREE_CHROMA and the base 2 logarithm of the minimum coding block size in luma samples for chroma CUs with treeType equal to DUAL TREE CHROMA in slices with slice type equal to 2 (1) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log 2_diff_min_qt_min_cb_chroma present in PHs referring to the SPS. The value of sps_log 2_diff_min_qt_min_cb_intra_slice_chroma shall be in the range of 0 to CtbLog 2SizeY−MinCbLog 2SizeY. inclusive. When not present, the value of sps_log 2_diff_min_qt_min_cb_intra_slice_chroma is inferred to be equal to 0. The base 2 logarithm of the minimum size in luma samples of a chroma leaf block resulting from quadtree splitting of a CTU with treeType equal to DUAL_TREE_CHROMA is derived as follows: MinQtLog 2SizeIntraC=sps_log 2_diff_min_qt_min_cb_intra_slice_chroma+MinCbLog 2SizeY sps_max_mtt_hierarchy_depth_intra_slice_chroma specifies the default maximum hierarchy depth for chroma coding units resulting from multi-type tree splitting of a chroma quadtree leaf with treeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default maximum hierarchy depth can be overridden by ph_max_mtt_hierarchy_depth_chroma present in PHs referring to the SPS. The value of sps_max_mtt_hierarchy_depth_intra_slice_chroma shall be in the range of 0 to 2*(CtbLog 2SizeY−MinCbLog 2SizeY), inclusive. When not present, the value of sps_max_mtt_hierarchy_depth_intra_slice_chroma is inferred to be equal to 0. sps_log 2_diff_max_bt_min_qt_intra_slice_chroma specifics the default difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a chroma coding block that can be split using a binary split and the minimum size (width or height) in luma samples of a chroma leaf block resulting from quadtree splitting of a chroma CTU with treeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log 2_diff_max_bt_min_qt_chroma present in PHs referring to the SPS. The value of sps_log 2_diff_max_bt_min_qt_intra_slice_chroma shall be in the range of 0 to CtbLog 2SizeY−MinQtLog 2SizeIntraC, inclusive. When sps_log 2_diff_max_bt_min_qt_intra_slice_chroma is not present, the value of sps_log 2_diff_max_bt_min_qt_intra_slice_chroma is inferred to be equal to 0. sps_log 2_diff_max_tt_min_qt_intra_slice_chroma specifies the default difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a chroma coding block that can be split using a ternary split and the minimum size (width or height) in luma samples of a chroma leaf block resulting from quadtree splitting of a chroma CTU with treeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log 2_diff_max_tt_min_qt_chroma present in PHs referring to the SPS. The value of sps_log 2_diff_max_tt_min_qt_intra_slice_chroma shall be in the range of 0 to CtbLog 2SizeY−MinQtLog 2SizeIntraC, inclusive. When sps_log 2_diff_max_tt_min_qt_intra_slice_chroma is not present, the value of sps_log 2_diff_max_tt_min_qt_intra_slice_chroma is inferred to be equal to 0. sps_max_luma_transform_size_64_flag equal to 1 specifies that the maximum transform size in luma samples is equal to 64. sps_max_luma_transform_size_64_flag equal to 0 specifies that the maximum transform size in luma samples is equal to 32. When CtbSizeY is less than 64, the value of sps_max_luma_transform_size_64_flag shall be equal to 0. The variables MinTbLog 2SizeY, MaxTbLog 2SizeY, MinTbSizeY, and MaxTbSizeY are derived as follows:

MinTbLog 2SizeY=2 MaxTbLog 2SizeY=sps_max_luma_transform_size_64_flag ? 6:5 MinTbSizeY=1<<MinTbLog 2SizeY) MaxTbSizeY=1<<MaxTbLog 2SizeY)

sps joint_cbcr_enabled_flag equal to 0 specifies that the joint coding of chroma residuals is disabled. sps_joint_cbcr_enabled_flag equal to 1 specifies that the joint coding of chroma residuals is enabled. When not present, the value of sps_joint_cbcr_enabled_flag is inferred to be equal to 0. same_qp_table_for_chroma equal to 1 specifies that only one chroma QP mapping table is signalled and this table applies to Cb and Cr residuals and additionally to joint Cb-Cr residuals when sps_joint_cbcr_enabled_flag is equal to 1. same_qp_table_for_chroma equal to 0 specifies that chroma QP mapping tables, two for Cb and Cr, and one additional for joint Cb-Cr when sps_joint_cbcr_enabled_flag is equal to 1, are signalled in the SPS. When same_qp_table_for_chroma is not present in the bitstream, the value of same_qp_table_for_chroma is inferred to be equal to 1. qp_table_start_minus26[i] plus 26 specifies the starting luma and chroma QP used to describe the i-th chroma QP mapping table. The value of qp_table_start_minus26[i] shall be in the range of −26−QpBdOffset to 36 inclusive. When qp_table_start_minus26[i] is not present in the bitstream, the value of qp_table_start_minus26[i] is inferred to be equal to 0. num_points_in_qp_table_minus1[i] plus 1 specifies the number of points used to describe the i-th chroma QP mapping table. The value of num_points_in_qp_table_minus1[i] shall be in the range of 0 to 63+QpBdOffset, inclusive. When num_points_in_qp_table_minus1 [0] is not present in the bitstream, the value of num_points_in_qp_table_minus1[0] is inferred to be equal to 0. delta_qp_in_val_minus1[i][j] specifies a delta value used to derive the input coordinate of the j-th pivot point of the i-th chroma QP mapping table. When delta_qp_in_val_minus1[0][j] is not present in the bitstream, the value of delta_qp_in_val_minus1[0][j] is inferred to be equal to 0. delta_qp_diff_val[i][j] specifies a delta value used to derive the output coordinate of the j-th pivot point of the i-th chroma QP mapping table. The i-th chroma QP mapping table ChromaQpTable[i] for i=0 . . . numQpTables−1 is derived as follows:

qpInVal[ i ][ 0 ] = qp_table_start_minus26[ i ] + 26 qpOutVal[ i ][ 0 ] = qpInVal[ i ][ 0 ] for( j = 0; j <= num_points_in_qp_table_minus1[ i ]; j++ ) {  qpInVal[ i ][ j + 1 ] = qpInVal[ i ][ j ] + delta_qp_in_val_minus1[   i ][ j ] + 1  qpOutVal[ i ][ j + 1 ] = qpOutVal[ i ][ j ] + (  delta_qp_in_val_minus1[ i ][ j ] {circumflex over ( )} delta_qp_diff_val[ i ][ j ] ) } ChromaQpTable[ i ][ qpInVal[ i ][ 0 ] ] = qpOutVal[ i ][ 0 ] for( k = qpInVal[ i ][ 0 ] − 1; k >= −QpBdOffset; k− − )  ChromaQpTable[ i ][ k ] = Clip3( −QpBdOffset, 63, ChromaQpTable[  i ][ k + 1 ] − 1 ) for( j = 0; j <= num_points_in_qp_table_minus1[ i ]; j++ ) {  sh = ( delta_qp_in_val_minus1[ i ][j ] + 1 ) >> 1  for( k = qpInVal[ i ][ j ] + 1, m = 1; k <= qpInval[ i ][ j + 1 ]; k++,  m++ )   ChromaQpTable[ i ][ k ] = ChromaQpTable[ i ][ qpInVal[ i ][ j ] ] +   ( ( qpOutVal[ i ][j + 1 ] − qpOutVal[ i ][j ] ) * m + sh ) / (   delta_qp_in_val_minus1[ i ][j] + 1 ) } for( k = qpInVal[ i ][ num_points_in_qp_table_minus1[ i ] + 1 ] + 1; k <= 63; k++ )  ChromaQpTable[ i ][ k ] = Clip3( −QpBdOffset, 63, ChromaQpTable[  i ][ k − 1 ] + 1 ) When same_qp_table_for_chroma is equal to 1, ChromaQpTable[1][k] and ChromaQpTable[2][k] are set equal to ChromaQpTable[0][k] for k in the range of −QpBdOffset to 63, inclusive.

It is a requirement of bitstream conformance that the values of qpInVal[i][j] and qpOutVal[i][j] shall be in the range of −QpBdOffset to 63, inclusive for i in the range of 0 to numQpTables−1, inclusive, and j in the range of 0 to num_points_in_qp_table_minus1[i]+1, inclusive.

sps_sao_enabled_flag equal to 1 specifies that the sample adaptive offset process is applied to the reconstructed picture after the deblocking filter process. sps_sao_enabled_flag equal to 0 specifies that the sample adaptive offset process is not applied to the reconstructed picture after the deblocking filter process. sps_alf_enabled_flag equal to 0 specifies that the adaptive loop filter is disabled. sps_alf_enabled_flag equal to 1 specifies that the adaptive loop filter is enabled. sps_ccalf_enabled_flag equal to 0 specifies that the cross-component adaptive loop filter is disabled. sps_ccalf_enabled_flag equal to 1 specifies that the cross-component adaptive loop filter may be enabled. sps_transform_skip_enabled_flag equal to 1 specifies that transform_skip_flag may be present in the transform unit syntax. sps_transform_skip_enabled_flag equal to 0 specifies that transform_skip_flag is not present in the transform unit syntax. log 2_transform_skip_max_size_minus2 specifies the maximum block size used for transform skip, and shall be in the range of 0 to 3, inclusive.

The variable MaxTsSize is set equal to 1>>(log 2_transform_skip_max_size_minus2+2). sps_bdpcm_enabled_flag equal to 1 specifics that intra_bdpcm_luma_flag and intra_bdpcm_chroma_flag may be present in the coding unit syntax for intra coding units. sps_bdpcm_enabled_flag equal to 0 specifies that intra_bdpcm_luma_flag and intra_bdpcm_chroma_flag are not present in the coding unit syntax for intra coding units. When not present, the value of sps_bdpcm_enabled_flag is inferred to be equal to 0.

sps_ref_wraparound_enabled_flag equal to 1 specifies that horizontal wrap-around motion compensation is applied in inter prediction. sps_ref_wraparound_enabled_flag equal to 0 specifies that horizontal wrap-around motion compensation is not applied. When the value of (CtbSizeY/MinCbSizeY+1) is greater than (pic_width_in_luma_samples/MinCbSizeY−1), where pic_width_in_luma_samples is the value of pic width in luma samples in any PPS that refers to the SPS, the value of sps_ref_wraparound_enabled_flag shall be equal to 0. sps_temporal_mvp_enabled_flag equal to 1 specifies that temporal motion vector predictors may be used in the CLVS. sps_temporal_mvp_enabled_flag equal to 0 specifies that temporal motion vector predictors are not used in the CLVS. sps_sbtmvp_enabled_flag equal to 1 specifies that subblock-based temporal motion vector predictors may be used in decoding of pictures with all slices having slice_type not equal to 1 in the CLVS. sps_sbtmvp_enabled_flag equal to 0 specifies that subblock-based temporal motion vector predictors are not used in the CLVS. When sps_sbtmvp_enabled_flag is not present, it is inferred to be equal to 0. sps_amvr_enabled_flag equal to 1 specifies that adaptive motion vector difference resolution is used in motion vector coding. amvr_enabled_flag equal to 0 specifies that adaptive motion vector difference resolution is not used in motion vector coding. sps_bdof_enabled_flag equal to 0 specifies that the bi-directional optical flow inter prediction is disabled. sps_bdof_enabled_flag equal to 1 specifies that the bi-directional optical flow inter prediction is enabled. sps_bdof_pic_present_flag equal to 1 specifies that ph_disable_bdof_flag is present in PHs referring to the SPS. sps_bdof_pic_present_flag equal to 0 specifies that ph_disable_bdof_flag is not present in PHs referring to the SPS. When sps_bdof_pic_present_flag is not present, the value of sps_bdof_pic_present_flag is inferred to be equal to 0. sps_smvd_enabled_flag equal to 1 specifies that symmetric motion vector difference may be used in motion vector decoding. sps_smvd_enabled_flag equal to 0 specifies that symmetric motion vector difference is not used in motion vector coding. sps_dmvr_enabled_flag equal to 1 specifics that decoder motion vector refinement based inter bi-prediction is enabled. sps_dmvr_enabled_flag equal to 0 specifies that decoder motion vector refinement based inter bi-prediction is disabled. sps_dmvr_pic_present_flag equal to 1 specifies that ph_disable_dmvr_flag is present in PHs referring to the SPS. sps_dmvr_pic_present_flag equal to 0 specifies that ph_disable_dmvr_flag is not present in PHs referring to the SPS. When sps_dmvr_pic_present_flag is not present, the value of sps_dmvr_pic_present_flag is inferred to be equal to 0. sps_mmvd_enabled_flag equal to 1 specifies that merge mode with motion vector difference is enabled. sps_mmvd_enabled_flag equal to 0 specifies that merge mode with motion vector difference is disabled. sps_isp_enabled_flag equal to 1 specifies that intra prediction with subpartitions is enabled. sps_isp_enabled_flag equal to 0 specifies that intra prediction with subpartitions is disabled. sps_mrl_enabled_flag equal to 1 specifies that intra prediction with multiple reference lines is enabled. sps_mrl_enabled_flag equal to 0 specifies that intra prediction with multiple reference lines is disabled. sps_mip_enabled_flag equal to 1 specifies that matrix-based intra prediction is enabled. sps_mip_enabled_flag equal to 0 specifies that matrix-based intra prediction is disabled. sps_cclm_enabled_flag equal to 0 specifies that the cross-component linear model intra prediction from luma component to chroma component is disabled. sps_cclm_enabled_flag equal to 1 specifies that the cross-component linear model ultra prediction from luma component to chroma component is enabled. When sps_cclm_enabled_flag is not present, it is inferred to be equal to 0. sps_chroma_horizontal_collocated_flag equal to 1 specifies that prediction processes operate in a manner designed for chroma sample positions that are not horizontally shifted relative to corresponding luma sample positions. sps_chroma_horizontal_collocated_flag equal to 0 specifies that prediction processes operate in a manner designed for chroma sample positions that are shifted to the right by 0.5 in units of luma samples relative to corresponding luma sample positions. When sps_chroma_horizontal_collocated_flag is not present, it is inferred to be equal to 1. sps_chroma_vertical_collocated_flag equal to 1 specifies that prediction processes operate in a manner designed for chroma sample positions that are not vertically shifted relative to corresponding luma sample positions. sps_chroma_vertical_collocated_flag equal to 0 specifies that prediction processes operate in a manner designed for chroma sample positions that are shifted downward by 0.5 in units of luma samples relative to corresponding luma sample positions. When sps_chroma_vertical_collocated_flag is not present, it is inferred to be equal to 1. sps_mts_enabled_flag equal to 1 specifics that sps_explicit_mts_intra_enabled_flag is present in the sequence parameter set RBSP syntax and sps_explicit_mts_inter_enabled_flag is present in the sequence parameter set RBSP syntax. sps_mts_enabled_flag equal to 0 specifies that sps_explicit_mts_intra_enabled_flag is not present in the sequence parameter set RB SP syntax and sps_explicit_mts_inter_enabled_flag is not present in the sequence parameter set RBSP syntax. sps_explicit_mts_intra_enabled_flag equal to 1 specifies that mts_idx may be present in ultra coding unit syntax. sps_explicit_nits_intra_enabled_flag equal to 0 specifies that mts_idx is not present in intra coding unit syntax. When not present, the value of sps_explicit_mts_intra_enabled_flag is inferred to be equal to 0. sps_explicit_mts_inter_enabled_flag equal to 1 specifies that mts_idx may be present in inter coding unit syntax. sps_explicit_mts_inter_enabled_flag equal to 0 specifies that mts_idx is not present in inter coding unit syntax. When not present, the value of sps_explicit_mts_inter_enabled_flag is inferred to be equal to 0. six_minus_max_num_merge_cand specifies the maximum number of merging motion vector prediction (MVP) candidates supported in the SPS subtracted from 6. The maximum number of merging MVP candidates, MaxNumMergeCand, is derived as follows:

MaxNumMergeCand=6−six_minus_max_num_merge_cand

The value of MaxNumMergeCand shall be in the range of 1 to 6, inclusive. sps_sbt_enabled_flag equal to 0 specifies that subblock transform for inter-predicted CUs is disabled. sps_sbt_enabled_flag equal to 1 specifies that subblock transform for inter-predicteds CU is enabled. sps_affine_enabled_flag specifies whether affine model based motion compensation can be used for inter prediction. If sps_affine_enabled_flag is equal to 0, the syntax shall be constrained such that no affine model based motion compensation is used in the CLVS, and inter_affine_flag and cu_affine_type_flag are not present in coding unit syntax of the CLVS. Otherwise (sps_affine_enabled_flag is equal to 1), affine model based motion compensation can be used in the CLVS. five_minus_max_num_subblock_merge_cand specifies the maximum number of subblock-based merging motion vector prediction candidates supported in the SPS subtracted from 5. sps_affine_type_flag specifies whether 6-parameter affine model based motion compensation can be used for inter prediction. If sps_affine_type_flag is equal to 0, the syntax shall be constrained such that no 6-parameter affine model based motion compensation is used in the CLVS, and cu_affine_type_flag is not present in coding unit syntax in the CLVS. Otherwise (sps_affine_type_flag is equal to 1), 6-parameter affine model based motion compensation can be used in the CLVS. When not present, the value of sps_affine_type_flag is inferred to be equal to 0. sps_affine_amvr_enabled_flag equal to 1 specifies that adaptive motion vector difference resolution is used in motion vector coding of affine inter mode. sps_affine_amvr_enabled_flag equal to 0 specifies that adaptive motion vector difference resolution is not used in motion vector coding of affine inter mode. When not present, the value of sps_affine_amvr_enabled_flag is inferred to be equal to 0. sps_affine_prof_enabled_flag specifies whether the prediction refinement with optical flow can be used for affine motion compensation. If sps_affine_prof_enabled_flag is equal to 0, the affine motion compensation shall not be refined with optical flow. Otherwise (sps_affine_prof_enabled_flag is equal to 1), the affine motion compensation can be refined with optical flow. When not present, the value of sps_affine_prof_enabled_flag is inferred to be equal to 0. sps_prof_pic_present_flag equal to 1 specifics that ph_disable_prof_flag is present in PHs referring to the SPS. sps_prof_pic_present_flag equal to 0 specifies that ph_disable_prof_flag is not present in PHs referring to the SPS. When sps_prof_pic_present_flag is not present, the value of sps_prof_pic_present_flag is inferred to be equal to 0. sps_palette_enabled_flag equal to 1 specifies that pred_mode_plt_flag may be present in the coding unit syntax. sps_palette_enabled_flag equal to 0 specifies that pred_mode_plt_flag is not present in the coding unit syntax. When sps_palette_enabled_flag is not present, it is inferred to be equal to 0. sps_act_enabled_flag equal to 1 specifies that adaptive colour transform may be used and the cu_act_enabled_flag may be present in the coding unit syntax. sps_act_enabled_flag equal to 0 specifies that adaptive colour transform is not used and cu_act_enabled_flag is not present in the coding unit syntax. When sps_act_enabled_flag is not present, it is inferred to be equal to 0. min_qp_prime_ts_minus4 specifies the minimum allowed quantization parameter for transform skip mode as follows:

QpPrimeTsMin=4+min_qp_prime_ts_minus4

The value of min_qp_prime_ts_minus4 shall be in the range of 0 to 48, inclusive. sps_bcw_enabled_flag specifies whether bi-prediction with CU weights can be used for inter prediction. If sps_bcw_enabled_flag is equal to 0, the syntax shall be constrained such that no bi-prediction with CU weights is used in the CLVS, and bcw_idx is not present in coding unit syntax of the CLVS. Otherwise (sps_bcw_enabled_flag is equal to 1), bi-prediction with CU weights can be used in the CLVS. sps_ibc_enabled_flag equal to 1 specifies that the IBC prediction mode may be used in decoding of pictures in the CLVS. sps_ibc_enabled_flag equal to 0 specifies that the IBC prediction mode is not used in the CLVS. When sps_ibc_enabled_flag is not present, it is inferred to be equal to 0. six_minus_max_num_ibc_merge_cand specifies the maximum number of IBC merging block vector prediction (BVP) candidates supported in the SPS subtracted from 6. The maximum number of IBC merging BVP candidates, MaxNumIbcMergeCand, is derived as follows:

if( sps_ibc_enabled_flag )  MaxNumIbcMergeCand = 6 −  six_minus_max_num_ibc_merge_cand else  MaxNumIbcMergeCand = 0 sps_ciip_enabled_flag specifies that ciip_flag may be present in the coding unit syntax for inter coding units. sps_ciip_enabled_flag equal to 0 specifies that ciip_flag is not present in the coding unit syntax for inter coding units. sps_fpel_mmvd_enabled_flag equal to 1 specifies that merge mode with motion vector difference is using integer sample precision. sps_fpel_mmvd_enabled_flag equal to 0 specifies that merge mode with motion vector difference can use fractional sample precision. sps_gpm_enabled_flag specifies whether geometric partition based motion compensation can be used for inter prediction. sps_gpm_enabled_flag equal to 0 specifies that the syntax shall be constrained such that no geometric partition based motion compensation is used in the CLVS, and merge_gpm_partition_idx, merge_gpm_idx0, and merge_gpm_idx1 are not present in coding unit syntax of the CLVS. sps_gpm_enabled_flag equal to 1 specifies that geometric partition based motion compensation can be used in the CLVS. When not present, the value of sps_gpm_enabled_flag is inferred to be equal to 0. max_num_merge_cand_minus_max_num_gpm_cand specifies the maximum number of geometric partitioning merge mode candidates supported in the SPS subtracted from MaxNumMergeCand. If sps_gpm_enabled_flag is equal to 1 and MaxNumMergeCand is greater than or equal to 3, the maximum number of geometric partitioning merge mode candidates, MaxNumGeoMergeCand, is derived as follows:

if( sps_gpm_enabled_flag && MaxNumMergeCand >= 3 )  MaxNumGpmMergeCand = MaxNumMergeCand −   max_num_merge_cand_minus_max_num_gpm_cand else if( sps_gpm_enabled_flag && MaxNumMergeCand = = 2 )  MaxNumMergeCand = 2 else  MaxNumGeoMergeCand = 0 The value of MaxNumGeoMergeCand shall be in the range of 2 to MaxNumMergeCand, inclusive. sps_lmcs_enabled_flag equal to 1 specifies that luma mapping with chroma scaling is used in the CLVS. sps_lmcs_enabled_flag equal to 0 specifies that luma mapping with chroma scaling is not used in the CLVS. sps_lfnst_enabled_flag equal to 1 specifies that lfnst_idx may be present in intra coding unit syntax. sps_lfnst_enabled_flag equal to 0 specifies that lfnst_idx is not present in intra coding unit syntax. sps_ladf_enabled_flag equal to 1, specifies that sps_num_ladf_intervals_minus2, sps_laclf_lowest_interval_qp_offset, sps_laclf_qp_offseft[i], and sps_ladf_delta_threshold_minus1[i] are present in the SPS. sps_num_ladf_intervals_minus2 plus 1 specifies the number of sps_ladf_delta_threshold_minus1 [i] and sps_ladf_qp_offset[i] syntax elements that are present in the SPS. The value of sps_num_ladf_intervals_minus2 shall be in the range of 0 to 3, inclusive. sps_ladf_lowest_interval_qp_offset specifies the offset used to derive the variable qP as specified. The value of sps_ladf_lowest_interval_qp_offset shall be in the range of −63 to 63, inclusive. sps_ladf_qp_offset[i] specifies the offset array used to derive the variable qP as specified. The value of sps_ladf_qp_offset[i] shall be in the range of −63 to 63, inclusive. sps_ladf_delta_threshold_minus1[i] is used to compute the values of SpsLadfIntervalLowerBound[i], which specifies the lower bound of the i-th luma intensity level interval. The value of sps_ladf_delta_threshold_minus1[i] shall be in the range of 0 to 2^(BitDepth)−3, inclusive. The value of SpsLadfintervalLowerBound[0] is set equal to 0. For each value of i in the range of 0 to sps_num_ladf_intervals_minus2, inclusive, the variable SpsLadfIntervalLowerBound[i+1] is derived as follows: SpsLadfIntervalLowerBound[i+1]=SpsLadfIntervalLowerBound[i]+sps_latlf delta_threshold_minus1[i]+1 log 2_parallel_merge_level_minus2 plus 2 specifies the value of the variable Log 2ParMrgLevel, which is used in the derivation process for spatial merging candidates as specified, the derivation process for motion vectors and reference indices in subblock merge mode as specified, and to control the invocation of the updating process for the history-based motion vector predictor list. The value of log 2parallel_merge_level_minus2 shall be in the range of 0 to CtbLog 2SizeY−2, inclusive. The variable Log 2ParMrgLevel is derived as follows: Log 2ParMrgLevel=log 2 parallel merge level minus2+2 sps_scaling_list_enabled_flag equal to 1 specifies that a scaling list is used for the scaling process for transform coefficients. sps_scaling_list_enabled_flag equal to 0 specifies that scaling list is not used for the scaling process for transform coefficients. sps_dep_quant_enabled_flag equal to 0 specifies that dependent quantization is disabled for pictures referring to the SPS. sps_dep_quant_enabled_flag equal to 1 specifies that dependent quantization may be enabled for pictures referring to the SPS. sps_sign_data_hiding_enabled_flag equal to 0 specifies that sign bit hiding is disabled for pictures referring to the SPS. sps_sign_data_hiding_enabled_flag equal to 1 specifies that sign bit hiding may be enabled for pictures referring to the SPS. When sps_sign_data_hiding_enabled_flag is not present, it is inferred to be equal to 0. sps_virtual_boundaries_enabled_flag equal to 1 specifies that disabling in-loop filtering across virtual boundaries may be applied in the coded pictures in the CLVS. sps_virtual_boundaries_enabled_flag equal to 0 specifies that disabling in-loop filtering across virtual boundaries is not applied in the coded pictures in the CLVS. In-loop filtering operations include the deblocking filter, sample adaptive offset filler, and adaptive loop filter operations. sps_virtual_boundaries_present_flag equal to 1 specifies that information of virtual boundaries is signalled in the SPS. sps_virtual_boundaries_present_flag equal to 0 specifies that information of virtual boundaries is not signalled in the SPS. When there is one or more than one virtual boundaries signalled in the SPS, the in-loop filtering operations are disabled across the virtual boundaries in pictures referring to the SPS. In-loop filtering operations include the deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. It is a requirement of bitstream conformance that when the value of res_change_in_clvs_allowed_flag is equal to 1, the value of sps_virtual_boundaries_present_flag shall be equal to 0. sps_num_ver_virtual_boundaries specifies the number of sps_virtual_boundaries_pos_x[i] syntax elements that are present in the SPS. When sps_num_ver_virtual_boundaries is not present, it is inferred to be equal to 0. sps_virtual_boundaries_pos_x[i] specifies the location of the i-th vertical virtual boundary in units of luma samples divided by 8. The value of sps_virtual_boundaries_pos_x[i] shall be in the range of 1 to Ceil(pic width in luma samples 8)−1, inclusive. sps_num_hor_virtual_boundaries specifies the number of sps_virtual_boundaries_pos_y[i] syntax elements that are present in the SPS. When sps_num_hor_virtual_boundaries is not present, it is inferred to be equal to 0. When sps_virtual_boundaries_enabled_flag is equal to 1 and sps_virtual_boundaries_present_flag is equal to 1, the sum of sps_num_ver_virtual_boundaries and sps_num_hor_virtual_boundaries shall be greater than 0. sps_virtual_boundaries_pos_y[i] specifies the location of the i-th horizontal virtual boundary in units of luma samples divided by 8. The value of sps_virtual_boundaries_pos_y[i] shall be in the range of 1 to Ceil(pic_height_in_luma_samples÷8)−1, inclusive. sps_genend_hrd_params_present_flag equal to 1 specifies that the syntax structure general_hrd_parameters( ) is present in the SPS RBSP syntax structure. sps_general_hrd_params_present_flag equal to 0 specifies that the syntax structure general_hrd_parameters( ) is not present in the SPS RBSP syntax structure. sps_sublayer_cpb_params_present_flag equal to 1 specifies that the syntax structure old_hrd_parameters( ) in the SPS RBSP includes HRD parameters for sublayer representations with TemporalId in the range of 0 to sps_max_sublayers_minus1, inclusive. sps_sublayer_cpb_params_present_flag equal to 0 specifies that the syntax structure ols_hrd_parameters( ) in the SPS RBSP includes HRD parameters for the sublayer representation with Temporand equal to sps_max_sublayers_minus1 only. When sps_max_sublayers_minus1 is equal to 0, the value of sps_sublayer_cpb_params_present_flag is inferred to be equal to 0. When sps_sublayer_cpb_params_present_flag is equal to 0, the HRD parameters for the sublayer representations with Temporand in the range of 0 to sps_max_sublayers_minus1−1, inclusive, are inferred to be the same as that for the sublayer representation with TemporalId equal to sps_max_sublayers_minus1. These include the HRD parameters starting from the fixed_pic_rate_general_flag[i] syntax element till the sublayer_hrd_parameters(i) syntax structure immediately under the condition “if(general_vcl_hrd_params_present_flag)” in the ols_hrd_parameters syntax structure. field_seq_flag equal to 1 indicates that the CLVS conveys pictures that represent fields. field_seq_flag equal to 0 indicates that the CLVS conveys pictures that represent frames. When general_frame_only_constraint_flag is equal to 1, the value of field_seq_flag shall be equal to 0. When field_seq_flag is equal to 1, a frame-field information SEI message shall be present for every coded picture in the CLVS. NOTE—The specified decoding process does not treat pictures that represent fields or frames differently. A sequence of pictures that represent fields would therefore be coded with the picture dimensions of an individual field. For example, pictures that represent 1080i fields would commonly have cropped output dimensions of 1920×540, while the sequence picture rate would commonly express the rate of the source fields (typically between 50 and 60 Hz), instead of the source frame rate (typically between 25 and 30 Hz). vui_parameters_present_flag equal to 1 specifics that the syntax structure vui_parameters( ) is present in the SPS RBSP syntax structure. vui_parameters_present_flag equal to 0 specifies that the syntax structure vui_parameters( ) is not present in the SPS RBSP syntax structure. sps_extension_flag equal to 0 specifies that no sps_extension_data_flag syntax elements are present in the SPS RBSP syntax structure. sps_extension_flag equal to 1 specifies that there are sps_extension_data_flag syntax elements present in the SPS RBSP syntax structure. sps_extension_data_flag may have any value. Its presence and value do not affect decoder conformance to profiles specified in this version of this Specification. Decoders conforming to this version of this Specification shall ignore all sps_extension_data_flag syntax elements.

As provided in Table 2, a NAL unit may include a picture parameter set syntax structure. Table 4 illustrates the syntax of the picture parameter set syntax structure provided in JVET-Q2001.

TABLE 4 De- scrip- tor pic_parameter_set_rbsp( ) {  pps_pic_parameter_set_id ue(v)  pps_seq_parameter_set_id u(4)  mixed_nalu_types_in_pic_flag u(1)  pic_width_in_luma_samples ue(v)  pic_height_in_luma_samples ue(v)  pps_conformance_window_flag u(1)  if( pps_conformance_window_flag ) {   pps_conf_win_left_offset ue(v)   pps_conf_win_right_offset ue(v)   pps_conf_win_top_offset ue(v)   pps_conf_win_bottom_offset ue(v)  }  scaling_window_explicit_signalling_flag u(1)  if( scaling_window_explicit_signalling_flag ) {   scaling_win_left_offset ue(v)   scaling_win_right_offset ue(v)   scaling_win_top_offset ue(v)   scaling_win_bottom_offset ue(v)  }  output_flag_present_flag u(1)  subpic_id_mapping_in_pps_flag u(1)  if( subpic_id_mapping_in_pps_flag ) {   pps_num_subpics_minus1 ue(v)   pps_subpic_id_len_minus1 ue(v)   for( i = 0; i <= pps_num_subpic_minus1; i++ )    pps_subpic_id[ i ] u(v)  }  no_pic_partition_flag u(1)  if( !no_pic_partition_flag ) {   pps_log2_ctu_size_minus5 u(2)   num_exp_tile_columns_minus1 ue(v)   num_exp_tile_rows_minus1 ue(v)   for( i = 0; i <= num_exp_tile_columns_minus1; i++ )    tile_column_width_minus1[ i ] ue(v)   for( i = 0; i <= num_exp_tile_rows_minus1; i++ )    tile_row_height_minus1[ i ] ue(v)   if( NumTilesInPic > 1 )    rect_slice_flag u(1)   if( rect_slice_flag )    single_slice_per_subpic_flag u(1)   if( rect_slice_flag && !single_slice_per_subpic_flag ) {    num_slices_in_pic_minus1 ue(v)    if( num_slices_in_pic_minus1 > 0 )     tile_idx_delta_present_flag u(1)    for( i = 0; i < num_slices_in_pic_minus1; i++ ) {     if( NumTileColumns > 1 )      slice_width_in_tiles_minus1[ i ] ue(v)     if( NumTileRows > 1 &&       ( tile_idx_delta_present_flag | | tileIdx %       NumTileColumns = = 0 ) )      slice_height_in_tiles_minus1[ i ] ue(v)     if( slice_width_in_tiles_minus1[ i ] = = 0 &&       slice_height_in_tiles_minus1[ i ] = = 0 &&       RowHeight[ SliceTopLeftTileIdx[ i ] /       NumTileColumns ] > 1 ) {      num_exp_slices_in_tile[ i ] ue(v)      numExpSlicesInTile = num_exp_slices_in_tile[ i ]      for( j = 0; j < numExpSlicesInTile; j++ )       exp_slice_height_in_ctus_minus1[ j ] ue(v)      i += NumSlicesInTile[ i ]     }     if( tile_idx_delta_present_flag && i <     num_slices_in_pic_minus1 )      tile_idx_delta[ i ] se(v)    }   }   loop_filter_across_tiles_enabled_flag u(1)   loop_filter_across_slices_enabled_flag u(1)  }  cabac_init_present_flag u(1)  for( i = 0; i < 2; i++ )   num_ref_idx_default_active_minus1[ i ] ue(v)  rpl1_idx_present_flag u(1)  init_qp_minus26 se(v)  cu_qp_delta_enabled_flag u(1)  pps_chroma_tool_offsets_present_flag u(1)  if( pps_chroma_tool_offsets_present_flag ) {   pps_cb_qp_offset se(v)   pps_cr_qp_offset se(v)   pps_joint_cbcr_qp_offset_present_flag u(1)   if( pps_joint_cbcr_qp_offset_present_flag )    pps_joint_cbcr_qp_offset_value se(v)   pps_slice_chroma_qp_offsets_present_flag u(1)   pps_cu_chroma_qp_offset_list_enabled_flag u(1)  }  if( pps_cu_chroma_qp_offset_list_enabled_flag ) {   chroma_qp_offset_list_len_minus1 ue(v)   for( i = 0; i <= chroma_qp_offset_list_len_minus1; i++ ) {    cb_qp_offset_list[ i ] se(v)    cr_qp_offset_list[ i ] se(v)    if( pps_joint_cbcr_qp_offset_present_flag )     joint_cbcr_qp_offset_list[ i ] se(v)   }  }  pps_weighted_pred_flag u(1)  pps_weighted_bipred_flag u(1)  deblocking_filter_control_present_flag u(1)  if( deblocking_filter_control_present_flag ) {   deblocking_filter_override_enabled_flag u(1)   pps_deblocking_filter_disabled_flag u(1)   if( !pps_deblocking_filter_disabled_flag ) {    pps_beta_offset_div2 se(v)    pps_tc_offset_div2 se(v)    pps_cb_beta_offset_div2 se(v)    pps_cb_tc_offset_div2 se(v)    pps_cr_beta_offset_div2 se(v)    pps_cr_tc_offset_div2 se(v)   }  }  rpl_info_in_ph_flag u(1)  if( deblocking_filter_override_enabled_flag )   dbf_info_in_ph_flag u(1)  sao_info_in_ph_flag u(1)  alf_info_in_ph_flag u(1)  if( ( pps_weighted_pred_flag | | pps_weighted_bipred_flag )  && rpl_present_in_ph_flag )   wp_info_in_ph_flag u(1)  qp_delta_info_in_ph_flag u(1)  pps_ref_wraparound_enabled_flag u(1)  if( pps_ref_wraparound_enabled_flag )   pps_ref_wraparound_offset ue(v)  picture_header_extension_present_flag u(1)  slice_header_extension_present_flag u(1)  pps_extension_flag u(1)  if( pps_extension_flag )   while( more_rbsp_data( ) )    pps_extension_data_flag u(1)  rbsp_trailing_bits( ) }

With respect to Table 4, JVET-Q2001 provides the following semantics:

A PPS RBSP shall be available to the decoding process prior to it being referenced, included in at least one AU with Temporand less than or equal to the Temporand of the PPS NAL unit or provided through external means.

All PPS NAL units with a particular value of pps_pic_parameter_set_id within a PU shall have the same content.

pps_pic_parameter_set_id identifies the PPS for reference by other syntax elements. The value of pps_pic_parameter_set_id shall be in the range of 0 to 63. inclusive.

PPS NAL units, regardless of the nuh_layer_id values, share the same value space of pps_pic_parameter_set_id.

Let ppsLayerId be the value of the nuh_layer_id of a particular PPS NAL unit, and vclLayerId be the value of the nuh_layer_id of a particular VCL NAL unit. The particular VCL NAL unit shall not refer to the particular PPS NAL unit unless ppsLayerId is less than or equal to vclLayerId and the layer with nuh_layer_id equal to ppsLayerId is included in at least one OLS that includes the layer with nuh_layer_id equal to vclLayerId.

pps_seq_parameter_set_id specifies the value of sps_seq_parameter_set_id for the SPS. The value of pps_seq_parameter_set_id shall be in the range of 0 to 15, inclusive. The value of pps_seqparameter_set_id shall be the same in all PPSs that are referred to by coded pictures in a CLVS. mixed_nalu_types_in_pic_flag equal to 1 specifies that each picture referring to the PPS has more than one VCL NAL unit, the VCL NAL units do not have the same value of nal_unit_type, and the picture is not an TRAP picture. mixed_nalu_types_in_pic_flag equal to 0 specifies that each picture referring to the PPS has one or more VCL NAL units and the VCL NAL units of each picture referring to the PPS have the same value of nal_unit_type. When no_mixed_nalu_types_in_pic_constraint_flag is equal to 1, the value of mixed_nalu_types_in_pic_flag shall be equal to 0. For each slice with a nal_unit_type value nalUnitTypeA in the range of IDR_W_RADL to CRA_NUT, inclusive, in a picture picA that also contains one or more slices with another value of nal_unit_type (i.e., the value of mixed_nalu_types_in_pic_flag for the picture picA is equal to 1), the following applies:

-   -   The slice shall belong to a subpicture subpicA for which the         value of the corresponding subpic_treated_as_pic_flag[i] is         equal to 1.     -   The slice shall not belong to a subpicture of picA containing         VCL NAL units with nal_unit_type not equal to nalUnitTypeA.     -   If nalUnitTypeA is equal to CRA, for all the following PUs         following the current picture in the CLVS in decoding order and         in output order, neither RefPicList[0] nor RefPicList[1] of a         slice in subpicA in those PUs shall include any picture         preceding picA in decoding order in an active entry.     -   Otherwise (i.e., nalUnitTypeA is equal to IDR_W_RADL or         IDR_N_LP), for all the PUs in the CLVS following the current         picture in decoding order, neither RefPicList[0] nor         RefPicList[1] of a slice in subpicA in those PUs shall include         any picture preceding picA in decoding order in an active entry.         -   NOTE—mixed_nalu_types_in_pic_flag equal to 1 indicates that             pictures referring to the PPS contain slices with different             NAL unit types, e.g., coded pictures originating from a             subpicture bitstream merging operation for which encoders             have to ensure matching bitstream structure and further             alignment of parameters of the original bitstreams. One             example of such alignments is as follows: When the value of             sps_idr_rpl_flag is equal to 0 and             mixed_nalu_types_in_pic_flag is equal to 1, a picture             referring to the PPS cannot have slices with nal_unit_type             equal to IDR_W_RADL or IDR_N_LP.             pic_width_in_luma_samples specifies the width of each             decoded picture referring to the PPS in units of luma             samples. pic_width_in_luma_samples shall not be equal to 0,             shall be an integer multiple of Max(8, MinCbSizeY), and             shall be less than or equal to             pic_width_max_in_luma_samples.

When res_change_in_clvs_allowed_flag equal to 0, the value of pic_width_in_luma_samples shall be equal to pic_width_max_in_luma_samples.

pic_height_in_luma_samples specifies the height of each decoded picture referring to the PPS hi units of luma samples. pic_height_in_luma_samples shall not be equal to 0 and shall be an integer multiple of Max(8, MinCbSizeY), and shall be less than or equal to pic_height_max_in_luma_samples.

When res_change_in_clvs_allowed_flag equal to 0, the value of pic_height_in_luma_samples shall be equal to pic_height_max_in_luma_samples. The variables PicWidthInCtbsY, PicHeightInCtbsY, PicSizeInCtbsY, PicWidthInMinCbsY, PicHeightInMinCbsY, PicSizeInMinCbsY, PicSizeInSamplesY, PicWidthInSamplesC and PicHeightInSamplesC are derived as follows:

-   -   PicWidthInCtbsY=Ceil(pic_width_in_luma_samples÷CtbSizeY)     -   PicHeightInCtbsY=Ceil(pic_height_in_luma_samples÷CtbSizeY)     -   PicSizeInCtbsY=PicWidthInCtbsY*PicHeightInCtbsY     -   PicWidthInMinCbsY=pic_width_in_luma_samples/MinCbSizeY     -   PicHeightInMinCbsY=pic_height_in_luma_samples/MinCbSizeY     -   PicSizeInMinCbsY=PicWidthInMinCbsY*PicHeightInMinCbsY     -   PicSizeInSamplesY=pic_width_in_luma_samples*pic_height_in_luma_samples     -   PicWidthInSamplesC=pic_width_in_luma_samples/SubWidthC     -   PicHeightInSamplesC=pic_height_in_luma_samples/SubHeightC         pps_conformance_window_flag equal to 1 indicates that the         conformance cropping window offset parameters follow next in the         PPS. pps_conformance_window_flag equal to 0 indicates that the         conformance cropping window offset parameters are not present in         the PPS.         pps_conf_win_left_offset, pps_conf_win_right_offset,         pps_conf_win_top_offset, and pps_conf_win_bottom_offset specify         the samples of the pictures in the CLVS that are output from the         decoding process, in terms of a rectangular region specified in         picture coordinates for output. When pps_conformance_window_flag         is equal to 0, the values of pps_conf_win_left_offset,         pps_conf_win_right_offset, pps_conf_win_top_offset, and         pps_conf_win_bottom_offset are inferred to be equal to 0.         The conformance cropping window contains the luma samples with         horizontal picture coordinates from         SubWidthC*pps_conf_win_left_offset to         pic_width_in_luma_samples−(SubWidthC*pps_conf_win_fight_offset+1)         and vertical picture coordinates from         SubHeightC*pps_conf_win_top_offset to         pic_height_in_luma_samplcs−(SubHeightC*pps_conf_win_bottom_offset+1),         inclusive.

The value of SubWidthC*(pps_conf_winieft_offset+pps_conf_win_right_offset) shall be less than pic_width_in_luma_samples, and the value of SubHeightC*(pps_conf_win_top_offset+pps_conf_win_bottom_offset) shall be less than pic_height_in_luma_samples.

When ChromaArrayType is not equal to 0, the corresponding specified samples of the two chroma arrays are the samples having picture coordinates (x/SubWidthC, y/SubHeightC), where (x,y) are the picture coordinates of the specified luma samples.

-   -   NOTE—The conformance cropping window offset parameters are only         applied at the output. All internal decoding processes are         applied to the uncropped picture size.         Let ppsA and ppsB be any two PPSs referring to the same SPS. It         is a requirement of bitstream conformance that, when ppsA and         ppsB have the same the values of pic_width_in_luma_samples and         pic_height_in_luma_samples, respectively, ppsA and ppsB shall         have the same values of pps_conf_win_left_offset,         pps_conf_win_right_offset, pps_conf_win_top offset, and         pps_conf_win_bottom_offset, respectively.         When pic_width_in_luma_samples is equal to         pic_width_max_in_luma_samples and pic_height_in_luma_samples is         equal to pic_height_max_in_luma_samples, it is a requirement of         bitstream conformance that pps_conf_win_left_offset,         pps_conf_win_right_offset, pps_conf_win_top offset, and         pps_conf_win_bottom_offset, are equal to         sps_conf_win_left_offset, sps_conf_win_right_offset,         sps_conf_win_top_offset, and sps_conf_win_bottom_offset,         respectively.         scaling_window_explicit_signalling_flag equal to 1 specifies         that the scaling window offset parameters are present in the         PPS. scaling_window_explicit_signalling_flag equal to 0         specifies that the scaling window offset parameters are not         present in the PPS. When res_change_in_clvs_allowed_flag is         equal to 0, the value of scaling_window_explicit_signalling_flag         shall be equal to 0.         scaling_win_left_offset, scaling_win_right_offset,         scaling_win_top_offset, and scaling_win_bottom_offset specify         the offsets that are applied to the picture size for scaling         ratio calculation. When not present, the values of         scaling_win_left_offset, scaling_win_right_offset,         scaling_win_top_offset, and scaling_win_bottom_offset are         inferred to be equal to SubWidthC*conf_win_left_offset,         SubWidthC*conf_win_right_offset, SubHeightC*coni win top offset,         and SubHeightC*coni win bottom offset, respectively.         The value of         SubWidthC*(scaling_win_left_offset+scaling_win_right_offset)         shall be less than pic_width_in_luma_samples, and the value of         SubHeightC*(scaling_win_top_offset+scaling_win_bottom_offset)         shall be less than pic_height_in_luma_samples.         The variables PicOutputWidthL and PicOutputHeightL are derived         as follows:     -   PicOutputWidthL=pic_width_in_luma_samples−SubWidthC*(scaling_win_right_offset+scaling_win_left_offset)     -   PicOutputHeightL=pic_height_in_luma_samples−SubWidthC*(scaling_win_bottom_offset+scaling_win_top_offset)         Let refPicOutputWidthL and refPicOutputHeightL be the         PicOutputWidthL and PicOutputHeightL, respectively, of a         reference picture of a current picture referring to this PPS. Is         a requirement of bitstream conformance that all of the following         conditions are satisfied:     -   PicOutputWidthL*2 shall be greater than or equal to         refPicWidthInLumaSamples.     -   PicOutputHeightL*2 shall be greater than or equal to         refPicHeightInLumaSamples.     -   PicOutputWidthL shall be less than or equal to         refPicWidthInLumaSamples*8.     -   PicOutputHeightL shall be less than or equal to         refPicHeightInLumaSamples*8.     -   PicOutputWidthL*pic_width_max_in_luma_samples shall be greater         than or equal to     -   refPicOutputWidthL*(pic_width_in_luma_samples−Max(8,         MinCbSizeY)).     -   PicOutputHeightL*pic_height_max_in_luma_samples shall be greater         than or equal to     -   refPicOutputHeightL*(pie height in luma samples−Max(8,         MinCbSizeY)).         output_flag_present_flag equal to 1 indicates that the         pic_output_flag syntax element is present in slice headers         referring to the PPS. output_flag_present_flag equal to 0         indicates that the pic_output_flag syntax element is not present         in slice headers referring to the PPS.         subpic_id_mapping_in_pps_flag equal to 1 specifies that the         subpicture ID mapping is signalled in the PPS.         subpic_id_mapping_in_pps_flag equal to 0 specifies that the         subpicture ID mapping is not signalled in the PPS. If         subpic_id_mapping_explicitly_signalled_flag is 0 or         subpic_id_mapping_in_sps_flag is equal to 1, the value of         subpic_id_mapping_in_pps_flag shall be equal to 0. Otherwise         (subpic_id_mapping_explicitly_signalled_flag is equal to 1 and         subpic_id_mapping_in_sps_flag is equal to 0), the value of         subpic_id_mapping_in_pps_flag shall be equal to 1.         pps_num_subpics_minus1 shall be equal to sps_num_subpics_minus1.         pps_subpic_id_len_minus1 shall be equal to         sps_subpic_id_len_minus1.         pps_subpic_id[i] specifies the subpicture ID of the i-th         subpicture. The length of the pps_subpic_id[i] syntax element is         pps_subpic_id_len_minus1+1 bits.

The variable SubpicIdVal[i], for each value of i in the range of 0 to sps_num_subpics_minus1, inclusive, is derived as follows:

-   -   for(i=0; i<=sps_num_subpics_minus1; i++)         -   if(subpic_id_mapping_explicitly_signalled_flag)             -   SubpicIdVal[i]=subpic_id_mapping_in_pps_flag ?                 pps_subpic_id[i]:sps_subpic_id[i]         -   else             -   SubpicIdVal[i]=i                 It is a requirement of bitstream conformance that both                 of the following constraints apply:     -   For any two differently values of i and j in the range of 0 to         sps_num_subpics_minus1, inclusive, SubpicIdVal[i] shall not be         equal to SubpicIdVal[j].     -   When the current picture is not the first picture of the CLVS,         for each value of i in the range of 0 to sps_num_subpics_minus1,         inclusive, if the value of SubpicIdVal[i] is not equal to the         value of SubpicIdVal[i] of the previous picture in decoding         order in the same layer, the nal_unit_type for all coded slice         NAL units of the subpicture in the current picture with         subpicture index i shall be equal to a particular value in the         range of IDR_W_RADL to CRA_NUT, inclusive.         no_pic_partition_flag equal to 1 specifies that no picture         partitioning is applied to each picture referring to the PPS.         no_pic_partition_flag equal to 0 specifies each picture         referring to the PPS may be partitioned into more than one tile         or slice.         It is a requirement of bitstream conformance that the value of         no_pic_partition_flag shall be the same for all PPSs that are         referred to by coded pictures within a CLVS.         It is a requirement of bitstream conformance that the value of         no_pic_partition_flag shall not be equal to 1 when the value of         sps_num_subpics_minus1+1 is greater than 1.         pps_log 2_ctu_size_minus5 plus 5 specifies the luma coding tree         block size of each CTU. pps_log 2_ctu_size_minus5 shall be equal         to sps_log 2_ctu_size_minus5.         num_exp_tile_columns_minus1 plus 1 specifies the number of         explicitly provided tile column widths. The value of         num_exp_tile_columns_minus1 shall be in the range of 0 to         PicWidthInCtbsY−1, inclusive. When no_pic_partition_flag is         equal to 1, the value of num_exp_tile_columns_minus1 is inferred         to be equal to 0.         num_exp_tile_rows_minus1 plus 1 specifies the number of         explicitly provided tile row heights. The value of         num_exp_tile_rows_minus1 shall be in the range of 0 to         PicHeightInCtbsY−1, inclusive. When no_pic_partition_flag is         equal to 1, the value of num tile rows minus1 is inferred to be         equal to 0.         tile_column_width_minus1[i] plus 1 specifies the width of the         i-th tile column in units of CTBs for i in the range of 0 to         num_exp_tile_columns_minus1−1, inclusive.         tile_column_width_minus1 [num_exp_tile_columns_minus1] is used         to derive the width of the tile columns with index greater than         or equal to num_exp_tile_columns_minus1 as specified. The value         of tile column width minus1 [i] shall be in the range of 0 to         PicWidthInCtbsY−1, inclusive. When not present, the value of         tile_column_width_minus1[0] is inferred to be equal to         PicWidthInCtbsY−1.         tile_row_height_minus1 [i] plus 1 specifies the height of the         i-th tile row in units of CTBs for i in the range of 0 to         num_exp_tile_rows_minus1−1, inclusive. tile row height         minus1[num_exp_tile_rows_minus1] is used to derive the height of         the tile rows with index greater than or equal to         num_exp_tile_rows_minus1 as specified. The value of         tile_row_height_minus1 [i] shall be in the range of 0 to         PicHeightInCtbsY−1, inclusive. When not present, the value of         tile_row_height_minus1 [0] is inferred to be equal to         PicHeightInCtbsY−1.         rect_slice_flag equal to 0 specifies that tiles within each         slice are in raster scan order and the slice information is not         signalled in PPS. rect_slice_flag equal to 1 specifics that         tiles within each slice cover a rectangular region of the         picture and the slice information is signalled in the PPS. When         not present, rect_slice_flag is inferred to be equal to 1. When         subpic_info_present_flag is equal to 1, the value of         rect_slice_flag shall be equal to 1.         single_slice_per_subpic_flag equal to 1 specifies that each         subpicture consists of one and only one rectangular slice.         single_slice_per_subpic_flag equal to 0 specifies that each         subpicture may consist of one or more rectangular slices.         When single_slice_per_subpic_flag is equal to 1,         num_slices_in_pic_minus1 is inferred to be equal to         sps_num_subpics_minus1. When not present, the value of         single_slice_per_subpic_flag is inferred to be equal to 0.         num_slices_in_pic_minus1 plus 1 specifies the number of         rectangular slices in each picture referring to the PPS. The         value of num_slices_in_pic_minus1 shall be in the range of 0 to         MaxSlicesPerPicture−1, inclusive, where MaxSlicesPerPicture is         specified. When no_pic_partition_flag is equal to 1, the value         of num_slices_in_pic_minus1 is inferred to be equal to 0.         tile_idx_delta_present_flag equal to 0 specifies that         tile_idx_delta values are not present in the PPS and all         rectangular slices in pictures referring to the PPS are         specified in raster order. tile_idx_delta_present_flag equal to         1 specifies that tile_idx_delta values may be present in the PPS         and all rectangular slices in pictures referring to the PPS are         specified in the order indicated by the values of         tile_idx_delta. When not present, the value of         tile_idx_delta_present_flag is inferred to be equal to 0.         slice_width_in_tiles_minus1 [i] plus 1 specifies the width of         the i-th rectangular slice in units of tile columns. The value         of slice_width_in_tiles_minus1[i] shall be in the range of 0 to         NumTileColumns−1, inclusive.         When slice width in tiles minus1[i] is not present, the         following applies:     -   If NumTileColumns is equal to 1, the value of         slice_width_in_tiles_minus1[i] is inferred to be equal to 0.     -   Otherwise, the value of slice_width_in_tiles_minus1[i] is         inferred as specified.         slice_height_in_tiles_minus1[i] plus 1 specifies the height of         the i-th rectangular slice in units of tile rows. The value of         slice_height_in_tiles_minus1 [i] shall be in the range of 0 to         NumTileRows−1, inclusive.         When slice height in tiles minus1 [i] is not present, the         following applies:     -   If NumTileRows is equal to 1, or tile_idx_delta_present_flag is         equal to 0 and tileIdx % NumTileColumns is greater than 0), the         value of slice_height_in_tiles_minus1 [i] is inferred to be         equal to 0.     -   Otherwise (NumTileRows is not equal to 1, and         tile_idx_delta_present_flag is equal to 1 or tileIdx %         NumTileColumns is equal to 0), when tile_idx_delta_present_flag         is equal to 1 or tileIdx % NumTileColumns is equal to 0, the         value of slice_height_in_tiles_minus1[i] is inferred to be equal         to slice_height_in_tiles_minus1 [i−1].         num_exp_slices_in_tile[i] specifies the number of explicitly         provided slice heights in the current tile that contains more         than one rectangular slices. The value of         num_exp_slices_in_tile[i] shall be in the range of 0 to         RowHeight[tileY]−1, inclusive, where tileY is the tile row index         containing the i-th slice. When not present, the value of         num_exp_slices_in_tile[i] is inferred to be equal to 0. When         num_exp_slices_in_tile[i] is equal to 0, the value of the         variable NumSlicesInTile[i] is derived to be equal to 1.         exp_slice_height_in_ctus_minus1[j] plus 1 specifies the height         of the j-th rectangular slice in the current tile in units of         CTU rows. The value of exp_slice_height_in_ctus_minus1[j] shall         be in the range of 0 to RowHeight[tileY]−1, inclusive, where         tileY is the file row index of the current tile.         When num_exp_slices_in_tile[i] is greater than 0, the variable         NumSlicesInTile[i] and SliceHeightInCtusMinus1[i+k] fork in the         range of 0 to NumSlicesInTile[i]−1 are derived as follows:

remainingHeightInCtbsY = RowHeight[ SliceTopLeftTileIdx[ i ] / NumTileColumns ] numExpSliceInTile = num_exp_slices_in_tile[ i ] for( j = 0; j < numExpSliceInTile − 1; j++ ) {  SliceHeightInCtusMinus1[ i++ ] = exp_slice_height_in_ctu_minus1[  j ]  remainingHeightInCtbsY −= SliceHeightInCtusMinus1[ j ] } uniformSliceHeightMinus1 = SliceHeightInCtusMinus1[ i − 1 ] while( remainingHeightInCtbsY >= (uniformSliceHeightMinus1 + 1) ) {  SliceHeightInCtusMinus1[ i++ ] = uniformSliceHeightMinus1  remainingHeightInCtbsY −= (uniformSliceHeightMinus1 + 1)  j++ } if( remainingHeightInCtbsY > 0 ) {  SliceHeightInCtusMinus1[ i++ ] = remainingHeightInCtbsY  j++ } NumSlicesInTile[ i ] = j tile_idx_delta[i] specifies the difference between the tile index of the first tile in the i-th rectangular slice and the tile index of the first tile in the (i+1)-th rectangular slice. The value of tile_idx_delta[i] shall be in the range of −NumTilesInPic+1 to NumTilesInPic−1, inclusive. When not present, the value of tile_idx_delta[i] is inferred to be equal to 0. When present, the value of tile_idx_delta[i] shall not be equal to 0. loop_filter_across_tiles_enabled_flag equal to 1 specifies that in-loop filtering operations may be performed across tile boundaries in pictures referring to the PPS. loop_filter_across_tiles_enabled_flag equal to 0 specifies that in-loop filtering operations are not performed across tile boundaries in pictures referring to the PPS. The in-loop filtering operations include the deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. When not present, the value of loop_filter_across_tiles_enabled_flag is inferred to be equal to 1. loop_filter_across_slices_enabled_flag equal to 1 specifies that in-loop filtering operations may be performed across slice boundaries in pictures referring to the PPS. loop_filter_across_slice_enabled_flag equal to 0 specifies that in-loop filtering operations are not performed across slice boundaries in pictures referring to the PPS. The in-loop filtering operations include the deblocking filter. sample adaptive offset filter, and adaptive loop filter operations. When not present, the value of loop_filter_across_slices_enabled_flag is inferred to be equal to 0. cabac_init_present_flag equal to 1 specifies that cabac_init_flag is present in slice headers referring to the PPS. cabac_init_present_flag equal to 0 specifies that cabac_init_flag is not present in slice headers referring to the PPS. num_ref_idx_default_active_minus1 [i] plus 1, when i is equal to 0, specifies the inferred value of the variable NumRefIdxActive[0] for P or B slices with num_ref_idx_active_override_flag equal to 0, and, when i is equal to 1, specifies the inferred value of NumRefIdxActive[1] for B slices with num_ref_idx_active_override_flag equal to 0. The value of num_ref_idx_default_active_minus1 [i] shall be in the range of 0 to 14, inclusive. rpl1_idx_present_flag equal to 0 specifies that ref_pic_list_sps_flag[1] and ref_pic_list_idx[1] are not present in the PH syntax structures or the slice headers for pictures referring to the PPS. rpl1_idx_present_flag equal to 1 specifies that ref_pic_list_sps_flag[1] and ref_pic_list_idx[1] may be present in the PH syntax structures or the slice headers for pictures referring to the PPS. init_qp_minus26 plus 26 specifies the initial value of SliceQp_(Y) for each slice referring to the PPS. The initial value of SliceQp_(Y) is modified at the picture level when a non-zero value of ph_qp_delta is decoded or at the slice level when a non-zero value of slice_qp_delta is decoded. The value of init_qp_minus26 shall be in the range of −(26+QpBdOffset) to +37, inclusive. cu_qp_delta_enabled_flag equal to 1 specifies that the ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are present in PHs referring to the PPS and cu_qp_delta_abs may be present in the transform unit syntax. cu_qp_delta_enabled_flag equal to 0 specifies that the ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are not present in PHs referring to the PPS and cu_qp_delta_abs is not present in the transform unit syntax. pps_chroma_tool_offsets_present_flag equal to 1 specifies that chroma tool offsets related syntax elements are present in the PPS RBSP syntax structure. pps_chroma_tool_offsets_present_flag equal to 0 specifies that chroma tool offsets related syntax elements are not present in in the PPS RBSP syntax structure. When ChromaArrayType is equal to 0, the value of pps_chroma_tool_offsets_present_flag shall be equal to 0. pps_cb_qp_offset and pps_cr_qp_offset specify the offsets to the luma quantization parameter Qp′ y used for deriving Qp′_(Cb) and Qp′_(Cr), respectively. The values of pps_cb_qp_offset and pps_cr_qp_offset shall be in the range of −12 to +12, inclusive. When ChromaArrayType is equal to 0, pps_cb_qp_offset and pps_cr_qp_offset are not used in the decoding process and decoders shall ignore their value. When not present, the values of pps_cb_qp_offset and pps_cr_qp_offset are inferred to be equal to 0. pps_joint_cbcr_qp_offset_present_flag equal to 1 specifies that pps_joint_cbcr_qp_offset_value and joint_cbcr_qp_offset_list[i] are present in the PPS RBSP syntax structure. pps_joint_cbcr_qp_offset_present_flag equal to 0 specifies that pps_joint_cbcr_qp_offset_value and joint_cbcr_qp_offset_list[i] are not present in the PPS RBSP syntax structure. When ChromaArrayType is equal to 0 or sps_joint_cbcr_enabled_flag is equal to 0, the value of pps_joint_cbcr_qp_offset_present_flag shall be equal to 0. When not present, the value of pps_joint_cbcr_qp_offset_present_flag is inferred to be equal to 0. pps_joint_cbcr_qp_offset_value specifies the offset to the luma quantization parameter Qp′ y used for deriving Qp′_(CbCr). The value of pps_joint_cbcr_qp_offset_value shall be in the range of −12 to +12, inclusive. When ChromaArrayType is equal to 0 or sps_joint_cbcr_enabled_flag is equal to 0, pps_joint_cbcr_qp_offset_value is not used in the decoding process and decoders shall ignore its value. When pps_joint_cbcr_qp_offset_present_flag is equal to 0, pps_joint_cbcr_qp_offset_value is not present and is inferred to be equal to 0. pps_slice_chroma_qp_offsets_present_flag equal to 1 specifies that the slice_cb_qp_offset and slice_cr_qp_offset syntax elements are present in the associated slice headers. pps_slice_chroma_qp_offsets_present_flag equal to 0 specifies that the slice_cb_qp_offset and slice_cr_qp_offset syntax elements are not present in the associated slice headers. When not present, the value of pps_slice_chroma_qp_offsets_present_flag is inferred to be equal to 0. pps_cu_chroma_qp_offset_list_enabled_flag equal to 1 specifies that the ph_cu_chromaqp_offset_subdiv_intra_slice and ph_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are present in PHs referring to the PPS and cu_chroma_qp_offset_flag may be present in the transform unit syntax and the palette coding syntax. pps_cu_chroma_qp_offset_list_enabled_flag equal to 0 specifies that the ph_cu_chromaqp_offset_subdiv_intra_slice and ph_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are not present in PHs referring to the PPS and the cu_chroma_qp_offset_flag is not present in the transform unit syntax and the palette coding syntax. When not present, the value of pps_cu_chroma_qp_offset_list_enabled_flag is inferred to be equal to 0. chroma_qp_offset_list_len_minus1 plus 1 specifies the number of cb_qp_offset_list[i], cr_qp_offset_list[i], and joint_cbcr_qp_offset_list[i], syntax elements that are present in the PPS RBSP syntax structure. The value of chroma_qp_offset_list_len_minus1 shall be in the range of 0 to 5, inclusive. cb_qp_offset_list[i], cr_qp_offset_list[i], and joint_cbcr_qp_offset_list[i], specify offsets used in the derivation of Qp′_(Cb), Qp′_(Cr), and Qp′_(CbCr), respectively. The values of cb_qp_offset_list[i]cr_qp_offset_list[i], and joint_cbcr_qp_offset_list[i] shall be in the range of −12 to +12, inclusive. When pps_joint_cbcr_qp_offset_present_flag is equal to 0, joint_cbcr_qp_offset_list[i] is not present and it is inferred to be equal to 0. pps_weighted_pred_flag equal to 0 specifies that weighted prediction is not applied to P slices referring to the PPS. pps_weighted_pred_flag equal to 1 specifies that weighted prediction is applied to P slices referring to the PPS. When sps_weighted_pred_flag is equal to 0, the value of pps_weighted_pred_flag shall be equal to 0. pps_weighted_bipred_flag equal to 0 specifies that explicit weighted prediction is not applied to B slices referring to the PPS. pps_weighted_bipred_flag equal to 1 specifies that explicit weighted prediction is applied to B slices referring to the PPS. When sps_weighted_bipred_flag is equal to 0, the value of pps_weighted_bipred_flag shall be equal to 0. deblocking_filter_control_present_flag equal to 1 specifies the presence of deblocking filter control syntax elements in the PPS. deblocking_filter_control_present_flag equal to 0 specifies the absence of deblocking filter control syntax elements in the PPS. deblocking_filter_override_enabled_flag equal to 1 specifies the presence of ph_deblocking_filter_override_flag in the PHs referring to the PPS or slice_deblocking_filter_override_flag in the slice headers referring to the PPS. deblocking_filter_override_enabled_flag equal to 0 specifies the absence of ph_deblocking_filter_override_flag in PHs referring to the PPS or slice_deblocking_filter_override_flag in slice headers referring to the PPS. When not present, the value of deblocking_filter_override_enabled_flag is inferred to be equal to 0. pps_deblocking_filter_disabled_flag equal to 1 specifies that the operation of deblocking filter is not applied for slices referring to the PPS in which slice_deblocking_filter_disabled_flag is not present. pps_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter is applied for slices referring to the PPS in which slice_deblocking_filter_disabled_flag is not present. When not present, the value of pps_deblocking_filter_disabled_flag is inferred to be equal to 0. pps_beta_offset_div2 and pps_tc_offset_div2 specify the default deblocking parameter offsets for β and tC (divided by 2) that are applied to the luma component for slices referring to the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the picture headers or the slice headers of the slices referring to the PPS. The values of pps_beta_offset_div2 and pps_tc_offset_div2 shall both be in the range of −12 to 12, inclusive. When not present, the values of pps_beta_offset_div2 and pps_tc_offset_div2 are both inferred to be equal to 0. pps_eb_beta_offset_div2 and pps_eb_tc_offset_div2 specify the default deblocking parameter offsets for β and tC (divided by 2) that are applied to the Cb component for slices referring to the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the picture headers or the slice headers of the slices referring to the PPS. The values of pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 shall both be in the range of −12 to 12, inclusive. When not present, the values of pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 are both inferred to be equal to 0. pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 specify the default deblocking parameter offsets for β and tC (divided by 2) that are applied to the Cr component for slices referring to the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the picture headers or the slice headers of the slices referring to the PPS. The values of pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 shall both be in the range of −12 to 12, inclusive. When not present, the values of pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 are both inferred to be equal to 0. rpl_info_in_ph_flag equal to 1 specifies that reference picture list information is present in the PH syntax structure and not present in slice headers referring to the PPS that do not contain a PH syntax structure. rpl_info_in_ph_flag equal to 0 specifies that reference picture list information is not present in the PH syntax structure and may be present in slice headers referring to the PPS that do not contain a PH syntax structure. dbf_info_in_ph_flag equal to 1 specifies that deblocking filter information is present in the PH syntax structure and not present in slice headers referring to the PPS that do not contain a PH syntax structure. dbf_info_in_ph_flag equal to 0 specifies that deblocking filter information is not present in the PH syntax structure and may be present in slice headers referring to the PPS that do not contain a PH syntax structure. When not present, the value of dbf_info_in_ph_flag is inferred to be equal to 0. sao_info_in_ph_flag equal to 1 specifies that SAO filter information is present in the PH syntax structure and not present in slice headers referring to the PPS that do not contain a PH syntax structure. sao_info_in_ph_flag equal to 0 specifies that SAO filter information is not present in the PH syntax structure and may be present in slice headers referring to the PPS that do not contain a PH syntax structure. alf_info_in_ph_flag equal to 1 specifies that ALF information is present in the PH syntax structure and not present in slice headers referring to the PPS that do not contain a PH syntax structure. alf_info_in_ph_flag equal to 0 specifies that ALF information is not present in the PH syntax structure and may be present in slice headers referring to the PPS that do not contain a PH syntax structure. wp_info_in_ph_flag equal to 1 specifies that weighted prediction information may be present in the PH syntax structure and not present in slice headers referring to the PPS that do not contain a PH syntax structure. wp_info_in_ph_flag equal to 0 specifies that weighted prediction information is not present in the PH syntax structure and may be present in slice headers referring to the PPS that do not contain a PH syntax structure. When not present, the value of wp_info_in_ph_flag is inferred to be equal to 0. qp_delta_info_in_ph_flag equal to 1 specifies that QP delta information is present in the PH syntax structure and not present in slice headers referring to the PPS that do not contain a PH syntax structure. qp_delta_info_in_ph_flag equal to 0 specifics that QP delta information is not present in the PH syntax structure and may be present in slice headers referring to the PPS that do not contain a PH syntax structure. pps_ref_wraparound_enabled_flag equal to 1 specifies that horizontal wrap-around motion compensation is applied in inter prediction. pps_ref_wraparound_enabled_flag equal to 0 specifies that horizontal wrap-around motion compensation is not applied. When the value of CtbSizeY/MinCbSizeY+1 is greater than pic_width_in_luma_samples/MinCbSizeY−1, the value of pps_ref_wraparound_enabled_flag shall be equal to 0. When sps_ref_wraparound_enabled_flag is equal to 0, the value of pps_ref_wraparound_enabled_flag shall be equal to 0. pps_ref_wraparound_offset plus (CtbSizeY/MinCbSizeY)+2 specifies the offset used for computing the horizontal wrap-around position in units of MinCbSizeY luma samples. The value of pps_ref_wraparound_offset shall be in the range of 0 to (pic_width_in_luma_samples/MinCbSizeY)−(CtbSizcY/MinCbSizeY)−2, inclusive. The variable PpsRefWraparoundOffset is set equal to pps_ref_wraparound_offset+(CtbSizeY/MinCbSizeY)+2. picture_header_extension_present_flag equal to 0 specifies that no PH extension syntax elements are present in PHs referring to the PPS. picture_header_extension_present_flag equal to 1 specifies that PH extension syntax elements are present in PHs referring to the PPS. picture_header_extension_present_flag shall be equal to 0 in bitstreams conforming to this version of this Specification. slice_header_extension_present_flag equal to 0 specifies that no slice header extension syntax elements are present in the slice headers for coded pictures referring to the PPS. slice_header_extension_present_flag equal to 1 specifies that slice header extension syntax elements are present in the slice headers for coded pictures referring to the PPS. slice_header_extension_present_flag shall be equal to 0 in bitstreams conforming to this version of this Specification. pps_extension_flag equal to 0 specifies that no pps_extension_data_flag syntax elements are present in the PPS RBSP syntax structure. pps_extension_flag equal to 1 specifies that there are pps_extension_data_flag syntax elements present in the PPS RBSP syntax structure. pps_extension_data_flag may have any value. Its presence and value do not affect decoder conformance to profiles specified in this version of this Specification. Decoders conforming to this version of this Specification shall ignore all pps_extension_data_flag syntax elements.

As provided in Table 2, a NAL unit may include a picture header rbsp( ) which includes a picture header syntax structure, picture header structure( ) Table 5 illustrates the syntax of the picture header syntax structure provided in JVET-Q2001.

TABLE 5 De- scrip- tor picture_header_structure( ) {  gdr_or_irap_pic_flag u(1)  if( gdr_or_irap_pic_flag )  gdr_pic_flag u(1)  ph_inter_slice_allowed_flag u(1)  if( ph_inter_slice_allowed_flag )  ph_intra_slice_allowed_flag u(1)  non_reference_picture_flag u(1)  ph_pic_parameter_set_id ue(v)  ph_pic_order_cnt_lsb u(v)  if( gdr_or_irap_pic_flag )  no_output_of_prior_pics_flag u(1)  if( gdr_pic_flag )  recovery_poc_cnt ue(v)   for( i = 0; i < NumExtraPhBits; i++ )  ph_extra_bit[ i ] u(1)  if( sps_poc_msb_flag ) {  ph_poc_msb_present_flag u(1)  if( ph_poc_msb_present_flag )   poc_msb_val u(v)  }  if( sps_alf_enabled_flag && alf_info_in_ph_flag ) {  ph_alf_enabled_flag u(1)  if( ph_alf_enabled_flag ) {   ph_num_alf_aps_ids_luma u(3)   for( i = 0; i < ph_num_alf_aps_ids_luma; i++ )   ph_alf_aps_id_luma[ i ] u(3)   if( ChromaArrayType != 0 )   ph_alf_chroma_idc u(2)   if( ph_alf_chroma_idc > 0 )   ph_alf_aps_id_chroma u(3)   if( sps_ccalf_enabled_flag ) {   ph_cc_alf_cb_enabled_flag u(1)   if( ph_cc_alf_cb_enabled_flag )    ph_cc_alf_cb_aps_id u(3)   ph_cc_alf_cr_enabled_flag u(1)   if( ph_cc_alf_cr_enabled_flag )    ph_cc_alf_cr_aps_id u(3)   }  }  }  if( sps_lmcs_enabled_flag ) {  ph_lmcs_enabled_flag u(1)  if( ph_lmcs_enabled_flag ) {   ph_lmcs_aps_id u(2)   if( ChromaArrayType != 0 )   ph_chroma_residual_scale_flag u(1)  }  }  if( sps_scaling_list_enabled_flag ) {  ph_scaling_list_present_flag u(1)  if( ph_scaling_list_present_flag )   ph_scaling_list_aps_id u(3)  }  if( sps_virtual_boundaries_enabled_flag &&  !sps_virtual_boundaries_present_flag ) {  ph_virtual_boundaries_present_flag u(1)  if( ph_virtual_boundaries_present_flag ) {   ph_num_ver_virtual_boundaries u(2)   for( i = 0; i < ph_num_ver_virtual_boundaries; i++ )   ph_virtual_boundaries_pos_x[ i ] u(13)   ph_num_hor_virtual_boundaries u(2)   for( i = 0; i < ph_num_hor_virtual_boundaries; i++ )   ph_virtual_boundaries_pos_y[ i ] u(13)  }  }  if( output_flag_present_flag )  pic_output_flag u(1)  if( rpl_info_in_ph_flag )  ref_pic_lists( )  if( partition_constraints_override_enabled_flag )  partition_constraints_override_flag u(1)  if( ph_intra_slice_allowed_flag ) {  if( partition_constraints_override_flag ) {   ph_log2_diff_min_qt_min_cb_intra_slice_luma ue(v)   ph_max_mtt_hierarchy_depth_intra_slice_luma ue(v)   if( ph_max_mtt_hierarchy_depth_intra_slice_luma !=   0 ) {   ph_log2_diff_max_bt_min_qt_intra_slice_luma ue(v)   ph_log2_diff_max_tt_min_qt_intra_slice_luma ue(v)   }   if( qtbtt_dual_tree_intra_flag ) {   ph_log2_diff_min_qt_min_cb_intra_slice_chroma ue(v)   ph_max_mtt_hierarchy_depth_intra_slice_chroma ue(v)   if( ph_max_mtt_hierarchy_depth_intra_slice_chroma   != 0 ) {    ph_log2_diff_max_bt_min_qt_intra_slice_chroma ue(v)    ph_log2_diff_max_tt_min_qt_intra_slice_chroma ue(v)   }   }  }  if( cu_qp_delta_enabled_flag )   ph_cu_qp_delta_subdiv_intra_slice ue(v)  if( pps_cu_chroma_qp_offset_list_enabled_flag )   ph_cu_chroma_qp_offset_subdiv_intra_slice ue(v)  }  if( ph_inter_slice_allowed_flag ) {  if( partition_constraints_override_flag ) {   ph_log2_diff_min_qt_min_cb_inter_slice ue(v)   ph_max_mtt_hierarchy_depth_inter_slice ue(v)   if( ph_max_mtt_hierarchy_depth_inter_slice != 0 ) {   ph_log2_diff_max_bt_min_qt_inter_slice ue(v)   ph_log2_diff_max_tt_min_qt_inter_slice ue(v)   }  }  if( cu_qp_delta_enabled_flag )   ph_cu_qp_delta_subdiv_inter_slice ue(v)  if( pps_cu_chroma_qp_offset_list_enabled_flag )   ph_cu_chroma_qp_offset_subdiv_inter_slice ue(v)  if( sps_temporal_mvp_enabled_flag ) {   ph_temporal_mvp_enabled_flag u(1)   if( ph_temporal_mvp_enabled_flag &&   rpl_info_in_ph_flag ) {   ph_collocated_from_l0_flag u(1)   if( ( ph_collocated_from_l0_flag &&    num_ref_entries[ 0 ][ RplsIdx[ 0 ] ] > 1 ) | |    ( !ph_collocated_from_l0_flag &&    num_ref_entries[ 1 ][ RplsIdx[ 1 ] ] > 1 ) )    ph_collocated_ref_idx ue(v)   }  }  mvd_l1_zero_flag u(1)  if( sps_fpel_mmvd_enabled_flag )   ph_fpel_mmvd_ enabled_flag u(1)  if( sps_bdof_pic_present_flag )   ph_disable_bdof_flag u(1)  if( sps_dmvr_pic_present_flag )   ph_disable_dmvr_flag u(1)  if( sps_prof_pic_present_flag )   ph_disable_prof_flag u(1)  if( ( pps_weighted_pred_flag | | pps_weighted_bipred_flag )  && wp_info_in_ph_flag )   pred_weight_table( )  }  if( qp_delta_info_in_ph_flag )  ph_qp_delta se(v)  if( sps_joint_cbcr_enabled_flag )  ph_joint_cbcr_sign_flag u(1)  if( sps_sao_enabled_flag && sao_info_in_ph_flag ) {  ph_sao_luma_enabled_flag u(1)  if( ChromaArrayType != 0 )   ph_sao_chroma_enabled_flag u(1)  }  if( sps_dep_quant_enabled_flag )  ph_dep_quant_enabled_flag u(1)  if( sps_sign_data_hiding_enabled_flag &&  !ph_dep_quant_enabled_flag )  pic_sign_data_hiding_enabled_flag u(1)  if( deblocking_filter_override_enabled_flag &&  dbf_info_in_ph_flag ) {  ph_deblocking_filter_override_flag u(1)  if( ph_deblocking_filter_override_flag ) {   ph_deblocking_filter_disabled_flag u(1)   if( !ph_deblocking_filter_disabled_flag ) {   ph_beta_offset_div2 se(v)   ph_tc_offset_div2 se(v)   ph_cb_beta_offset_div2 se(v)   ph_cb_tc_offset_div2 se(v)   ph_cr_beta_offset_div2 se(v)   ph_cr_tc_offset_div2 se(v)   }  }  }  if( picture_header_extension_present flag ) {  ph_extension_length ue(v)  for( i = 0; i < ph_extension_length; i++)   ph_extension_data_byte[ i ] u(8)  } }

With respect to Table 5, JVET-Q2001 provides the following semantics:

The PH syntax structure contains information that is common for all slices of the coded picture associated with the PH syntax structure.

gdr_or_irap_pic_flag equal to 1 specifies that the current picture is a GDR or IRAP picture. gdr_or_irap_pic_flag equal to 0 specifies that the current picture may or may not be a GDR or IRAP picture. gdr_pic_flag equal to 1 specifies the picture associated with the PH is a GDR picture. gdr_pic_flag equal to 0 specifies that the picture associated with the PH is not a GDR picture. When not present, the value of gdr_pic_flag is inferred to be equal to 0. When gdr_enabled_flag is equal to 0, the value of gdr_pic_flag shall be equal to 0. ph_inter_slice_allowed_flag equal to 0 specifies that all coded slices of the picture have slice_type equal to 2. ph_inter_slice_allowed_flag equal to 1 specifies that there may or may not be one or more coded slices in the picture that have slice_type equal to 0 or 1. ph_intra_slice_allowed_flag equal to 0 specifies that all coded slices of the picture have slice_type equal to 0 or 1. ph_intra_slice_allowed_flag equal to 1 specifies that there may or may not be one or more coded slices in the picture that have slice_type equal to 2. When not present, the value of ph_intra_slice_allowed_flag is inferred to be equal to 1.

-   -   NOTE—For bitstreams that are supposed to work subpicture based         bitstream merging without the need of changing PH NAL units, the         encoder is expected to set the values of both         ph_inter_slice_allowed_flag and ph_intra_slice_allowed_flag         equal to 1.         non_reference_picture_flag equal to 1 specifies the picture         associated with the PH is never used as a reference picture.         non_reference_picture_flag equal to 0 specifies the picture         associated with the PH may or may not be used as a reference         picture.         ph_pic_parameter_set_id specifies the value of         pps_pic_parameter_set_id for the PPS in use. The value of         ph_pic_parameter_set_id shall be in the range of 0 to 63,         inclusive.         It is a requirement of bitstream conformance that the value of         Temporand of the PH shall be greater than or equal to the value         of Temporand of the PPS that has pps_pic_parameter_set_id equal         to ph_pic_parameter_set_id.         ph_pic_order_cnt_lsb specifies the picture order count modulo         MaxPicOrderCntLsb for the current picture. The length of the         ph_pic_order_cnt_lsb syntax element is log 2         max_pic_order_cnt_lsb_minus4+4 bits. The value of the         ph_pic_order_cntisb shall be in the range of 0 to         MaxPicOrderCntLsb−1, inclusive.         no_output_of_prior_pics_flag affects the output of         previously-decoded pictures in the DPB after the decoding of a         CLVSS picture that is not the first picture in the bitstream as         specified.         recovery_poc_cnt specifies the recovery point of decoded         pictures in output order. If the current picture is a GDR         picture that is associated with the PH, and there is a picture         picA that follows the current GDR picture in decoding order in         the CLVS that has PicOrderCntVal equal to the PicOrderCntVal of         the current GDR picture plus the value of recovery_poc_cnt, the         picture picA is referred to as the recovery point picture.         Otherwise, the first picture in output order that has         PicOrderCntVal greater than the PicOrderCntVal of the current         picture plus the value of recovery_poc_cnt is referred to as the         recovery point picture. The recovery point picture shall not         precede the current GDR picture in decoding order. The value of         recovery_poc_cnt shall be in the range of 0 to         MaxPicOrderCntLsb−1, inclusive.         When the current picture is a GDR picture, the variable         RpPicOrderCntVal is derived as follows:     -   RpPicOrderCntVal=PicOrderCntVal+recovery_poc_cnt     -   NOTE—When gdr_enabled_flag is equal to 1 and PicOrderCntVal of         the current picture is greater than or equal to RpPicOrderCntVal         of the associated GDR picture, the current and subsequent         decoded pictures in output order are exact match to the         corresponding pictures produced by starting the decoding process         from the previous IRAP picture, when present, preceding the         associated GDR picture in decoding order.         ph_extra_bit[i] may be equal to 1 or 0. Decoders conforming to         this version of this Specification shall ignore the value of         ph_extra_bit[i]. Its value does not affect decoder conformance         to profiles specified in this version of specification.         ph_poc_msb_present_flag equal to 1 specifies that the syntax         element poc_msb_val is present in the PH.         ph_poc_msb_present_flag equal to 0 specifies that the syntax         element poc_msb_val is not present in the PH. When         vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id] ] is         equal to 0 and there is a picture in the current AU in a         reference layer of the current layer, the value of         ph_poc_insb_present_flag shall be equal to 0.         poc_msb_val specifies the POC MSB value of the current picture.         The length of the syntax element poc_msb_val is         poc_msb_len_minus1+1 bits.         ph_alf_enabled_flag equal to 1 specifies that adaptive loop         filter is enabled for all slices associated with the PH and may         be applied to Y, Cb, or Cr colour component in the slices.         ph_alf_enabled_flag equal to 0 specifies that adaptive loop         filter may be disabled for one, or more, or all slices         associated with the PH. When not present, ph_alf_enabled_flag is         inferred to be equal to 0.         ph_num_alf_aps_ids_luma specifies the number of ALF APSs that         the slices associated with the PH refers to.         ph_alf_aps_ids_luma[i] specifies the adaptation_parameter_set_id         of the i-th ALF APS that the luma component of the slices         associated with the PH refers to.         The value of alf_luma_filter_signal_flag of the APS NAL unit         having aps_params_type equal to ALF_APS and         adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i] shall         be equal to 1.         The TemporalId of the APS NAL unit having aps_params_type equal         to ALF_APS and adaptation_parameter_set_id equal to         ph_alf_aps_id_luma[i] shall be less than or equal to the         TemporalId of the picture associated with the PH.         ph_alf_chroma_idc equal to 0 specifies that the adaptive loop         filter is not applied to Cb and Cr colour components.         ph_alf_chroma_idc equal to 1 indicates that the adaptive loop         filter is applied to the Cb colour component. ph_alf_chroma_idc         equal to 2 indicates that the adaptive loop filter is applied to         the Cr colour component. ph_alf_chroma_idc equal to 3 indicates         that the adaptive loop filter is applied to Cb and Cr colour         components. When ph_alf_chroma_idc is not present, it is         inferred to be equal to 0.         ph_alf_aps_id_chroma specifies the adaptation_parameter_set_id         of the ALF APS that the chroma component of the slices         associated with the PH refers to.         The value of alf_chroma_filter_signal_flag of the APS NAL unit         having aps_params_type equal to ALF_APS and adaptation         parameter_set_id equal to ph_alf_aps_id_chroma shall be equal to         1.         The TemporalId of the APS NAL unit having aps_params_type equal         to ALF_APS and adaptation parameter_set_id equal to         ph_alf_aps_id_chroma shall be less than or equal to the         TemporalId of the picture associated with the PH.         ph_cc_alf_cb_enabled_flag equal to 1 specifics that         cross-component filter for Cb colour component is enabled for         all slices associated with the PH and may be applied to Cb         colour component in the slices. ph_cc_alf_cb_enabled_flag equal         to 0 specifies that cross-component filter for Cb colour         component may be disabled for one, or more. or all slices         associated with the PH. When not present,         ph_cc_alf_cb_enabled_flag is inferred to be equal to 0.         ph_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id of         the ALF APS that the Cb colour component of the slices         associated with the PH refers to.         The value of alf_cc_cb_filter_signal_flag of the APS NAL unit         having aps_params_type equal to ALF_APS and adaptation         parameter_set_id equal to ph_cc_alf_cb_aps_id shall be equal to         1.         ph_cc_alf_cr_enabled_flag equal to 1 specifies that         cross-component filter for Cr colour component is enabled for         all slices associated with the PH and may be applied to Cr         colour component in the slices. ph_cc_alf_cr_enabled_flag equal         to 0 specifies that cross-component filter for Cr colour         component may be disabled for one, or more, or all slices         associated with the PH. When not present,         ph_cc_alf_cr_enabled_flag is inferred to be equal to 0.         ph_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id of         the ALF APS that the Cr colour component of the slices         associated with the PH refers to.         The value of alf_cc_cr_filter_signal_flag of the APS NAL unit         having aps_params_type equal to ALF_APS and adaptation         parameter_set_id equal to ph_cc_alf_cr_aps_id shall be equal to         1.         ph_lmcs_enabled_flag equal to 1 specifies that luma mapping with         chroma scaling is enabled for all slices associated with the PH.         ph_lmcs_enabled_flag equal to 0 specifies that luma mapping with         chroma scaling may be disabled for one, or more, or all slices         associated with the PH. When not present, the value of         ph_lmcs_enabled_flag is inferred to be equal to 0.         ph_lmcs_aps_id specifies the adaptation_parameter_set_id of the         LMCS APS that the slices associated with the PH refers to. The         TemporalId of the APS NAL unit having aps_params_type equal to         LMCS_APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id         shall be less than or equal to the TemporalId of the picture         associated with PH.         ph_chroma_residual_scale_flag equal to 1 specifies that chroma         residual scaling is enabled for the all slices associated with         the PH. ph_chroma_residual_scale_flag equal to 0 specifies that         chroma residual scaling may be disabled for one, or more, or all         slices associated with the PH. When         ph_chroma_residual_scale_flag is not present, it is inferred to         be equal to 0.         ph_scaling_list_present_flag equal to 1 specifics that the         scaling list data used for the slices associated with the PH is         derived based on the scaling list data contained in the         referenced scaling list APS. ph_scaling_list_present_flag equal         to 0 specifies that the scaling list data used for the slices         associated with the PH is set to be equal to 16. When not         present, the value of ph_scaling_list_present_flag is inferred         to be equal to 0.         ph_scaling_list_aps_id specifies the adaptation_parameter_set_id         of the scaling list APS. The TemporalId of the APS NAL unit         having aps_params_type equal to SCALING_APS and         aclaptation_parameter_set_id equal to ph_scaling_list_aps_id         shall be less than or equal to the TemporalId of the picture         associated with PH.         ph_virtual_boundaries_present_flag equal to 1 specifies that         information of virtual boundaries is signalled in the PH.         ph_virtual_boundaries_present_flag equal to 0 specifies that         information of virtual boundaries is not signalled in the PH.         When there is one or more than one virtual boundaries signalled         in the PH, the in-loop filtering operations are disabled across         the virtual boundaries in the picture. The in-loop filtering         operations include the deblocking filter, sample adaptive offset         filter, and adaptive loop filter operations. When not present,         the value of ph_virtual_boundaries_present_flag is inferred to         be equal to 0.         It is a requirement of bitstream conformance that, when         subpic_info_present_flag is equal to 1, the value of         ph_virtual_boundaries_present_flag shall be equal to 0.         The variable VirtualBoundariesPresentFlag is derived as follows:     -   VirtualBoundariesPresentFlag=0     -   if(sps_virtual_boundaries_enabled_flag)         -   VirtualBoundariesPresentFlag=sps virtual             boundaries_present_flag∥ph_virtual_boundaries_present_flag             ph_num_ver_virtual_boundaries specifies the number of             ph_virtual_boundaries_pos_x[i] syntax elements that are             present in the PH. When ph_num_ver_virtual_boundaries is not             present, it is inferred to be equal to 0.             The variable NumVerVirtualBoundaries is derived as follows:     -   NumVerVirtualBoundaries=0     -   if(sps_virtualboundaries_enabled_flag)         -   NumVerVirtualBoundaries=sps_virtual_boundaries_present_flag             ?             -   sps_num_vcr_virtual_boundarics:ph_num_ver_virtual_boundaries                 ph_virtual_boundaries_pos_x[i] specifics the location of                 the i-th vertical virtual boundary in units of luma                 samples divided by 8. The value of                 ph_virtual_boundaries_pos_x[i] shall be in the range of                 1 to Ceil(pic_width_in_luma_samples÷8)−1, inclusive.

The list VirtualBoundariesPosX[i] for i ranging from 0 to NumVerVirtualBoundaries−1, inclusive, in units of luma samples, specifying the locations of the vertical virtual boundaries, is derived as follows:

-   -   for(i=0; i<NumVerVirtualBoundaries; i++)         -   VirtualBoundariesPosX[i]=(sps_virtual_boundaries_present_flag             ?             -   sps_virtual_boundaries_pos_x[i]:                 ph_virtual_boundaries_pos_x[i])*8                 The distance between any two vertical virtual boundaries                 shall be greater than or equal to CtbSizeY luma samples.                 ph_num_hor_virtual_boundaries specifies the number of                 ph_virtual_boundaries_pos_y[i] syntax elements that are                 present in the PH. When ph_num_hor_virtual_boundaries is                 not present, it is inferred to be equal to 0.                 The parameter NumHorVirtualBoundaries is derived as                 follows:     -   NumHorVirtualBoundaries=0     -   if(sps_virtual_boundaries_enabled_flag)         -   NumHorVirtualBoundarics=sps_virtual_boundaries_prescnt_flag             ?             -   sps_num_hor_virtual_boundaries:ph_num_hor_virtual_boundaries                 When sps_virtual_boundaries_enabled_flag is equal to 1                 and ph_virtual_boundaries_present_flag is equal to 1,                 the sum of ph_num_ver_virtual_boundaries and                 ph_num_hor_virtual_boundaries shall be greater than 0.                 ph_virtual_boundaries_pos_y[i] specifies the location of                 the i-th horizontal virtual boundary in units of luma                 samples divided by 8. The value of                 ph_virtual_boundaries_pos_y[i] shall be in the range of                 1 to Ceil(pic_height_in_luma_samples÷8)−1, inclusive.                 The list VirtualBoundariesPosY[i] for i ranging from 0                 to NumHorVirtualBoundaries−1, inclusive, in units of                 luma samples, specifying the locations of the horizontal                 virtual boundaries, is derived as follows:     -   for(i=0; i<NumHorVirtualBounclaries; i++)         -   VirtualBoundariesPosY[i]=(sps_virtual_boundaries_present_flag             ?             -   sps_virtual_boundaries_pos_y[i]:ph_virtual_boundaries_pos_y[i])*8                 The distance between any two horizontal virtual                 boundaries shall be greater than or equal to CtbSizeY                 luma samples.                 pic_output_flag affects the decoded picture output and                 removal processes as specified. When pic_output_flag is                 not present, it is inferred to be equal to 1.                 partition_constraints_override_flag equal to 1 specifies                 that partition constraint parameters are present in the                 PH. partition_constraints_override_flag equal to 0                 specifies that partition constraint parameters are not                 present in the PH. When not present, the value of                 partition_constraints_override_flag is inferred to be                 equal to 0.                 ph_log 2_diff_min_qt_min_cb_intra_slice_luma specifies                 the difference between the base 2 logarithm of the                 minimum size in luma samples of a luma leaf block                 resulting from quadtree splitting of a CTU and the base                 2 logarithm of the minimum coding block size in luma                 samples for luma CUs in the slices with slice_type equal                 to 2 (I) associated with the PH. The value of ph_log                 2_diff_min_qt_min_cb_intra_slice_luma shall be in the                 range of 0 to CtbLog 2SizeY−MinCbLog 2SizeY, inclusive.                 When not present, the value of ph_log                 2_diff_min_qt_min_cb_luma is inferred to be equal to                 sps_log 2_diff_min_qt_min_cb_intra_slice_luma.                 ph_max_mtt_hierarehy_depth_intra_slice_luma specifies                 the maximum hierarchy depth for coding units resulting                 from multi-type tree splitting of a quadtree leaf in                 slices with slice_type equal to 2 (I) associated with                 the PH. The value of                 ph_max_mtt_hierarchy_depth_intra_slice_luma shall be in                 the range of 0 to 2*(CtbLog 2SizeY−MinCbLog 2SizeY),                 inclusive. When not present, the value of                 ph_max_mtt_hierarchy_depth_intra_slice_luma is inferred                 to be equal to                 sps_max_mtt_hierarchy_depth_ultra_slice_luma.                 ph_log 2_diff_max_bt_min_qt_intra_slice_luma specifies                 the difference between the base 2 logarithm of the                 maximum size (width or height) in luma samples of a luma                 coding block that can be split using a binary split and                 the minimum size (width or height) in luma samples of a                 luma leaf block resulting from quadtree splitting of a                 CTU in slices with slice_type equal to 2 (1) associated                 with the PH. The value of ph_log                 2_diff_max_bt_min_qt_intra_slice_luma shall be in the                 range of 0 to CtbLog 2SizeY−MinQtLog 2SizeIntraY,                 inclusive. When not present, the value of ph_log                 2_diff_max_bt_min_qt_infra_slice_luma is inferred to be                 equal to sps_log 2_diff_max_bt_min_qt_intra_slice_luma.                 ph_log 2_diff_max_tt_min_qt_intra_slice_luma specifies                 the difference between the base 2 logarithm of the                 maximum size (width or height) in luma samples of a luma                 coding block that can be split using a ternary split and                 the minimum size (width or height) in luma samples of a                 luma leaf block resulting from quadtree splitting of a                 CTU in slices wills slice_type equal to 2 (1) associated                 wills the PH. The value of ph_log                 2_diff_max_tt_min_qt_intra_slice_luma shall be in the                 range of 0 to CtbLog 2SizeY−MinQtLog 2SizeIntraY,                 inclusive. When not present, the value of ph_log                 2_diff_max_tt_min_qt_intra_slice_luma is inferred to be                 equal to sps_log 2_diff_max_tt_min_qt_intra_slice_luma.                 ph_log 2_diff_min_qt_min_cb_intra_slice_chroma specifies                 the difference between the base 2 logarithm of the                 minimum size in luma samples of a chroma leaf block                 resulting from quadtree splitting of a chroma CTU with                 treeType equal to DUAL_TREE_CHROMA and the base 2                 logarithm of the minimum coding block size in luma                 samples for chroma CUs with treeType equal to                 DUAL_TREE_CHROMA in slices with slice_type equal to                 2 (1) associated with the PH. The value of ph_log                 2_diff_min_qt_min_cb_intra_slice_chroma shall be in the                 range of 0 to CtbLog 2SizeY−MinCbLog 2SizeY, inclusive.                 When not present, the value of ph_log                 2_diff_min_qt_min_cb_intra_slice_chroma is inferred to                 be equal to sps_log                 2_diff_min_qt_min_cb_intra_slice_chroma.                 ph_max_mtt_hierarchy_depth_intra_slice_chroma specifies                 the maximum hierarchy depth for chroma coding units                 resulting from multi-type tree splitting of a chroma                 quadtree leaf with treeType equal to DUAL_TREE_CHROMA in                 slices with slice_type equal to 2 (I) associated with                 the PH. The value of                 ph_max_mtt_hierarchy_depth_intra_slice_chroma shall be                 in the range of 0 to 2*(CtbLog 2SizeY−MinCbLog 2SizeY),                 inclusive. When not present, the value of                 ph_max_mtt_hierarchy_depth_intra_slice_chroma is                 inferred to be equal to                 sps_max_mtt_hierarchy_depth_intra_slice_chroma.

ph_log 2_diff_max_bt_min_qt_intra_slice_chroma specifies the difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a chroma coding block that can be split using a binary split and the minimum size (width or height) in luma samples of a chroma leaf block resulting from quadtree splitting of a chroma. CTU with treeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I) associated with the PH. The value of ph_log 2_diff_max_bt_min_qt_intra_slice_chroma shall be in the range of 0 to CtbLog 2SizeY−MinQtLog 2SizeIntraC, inclusive. When not present, the value of ph_log 2_diff_max_bt_min_qt_intra_slice_chroma is inferred to be equal to sps_log 2_diff_max_bt_min_qt_intra_slice_chroma.

ph_log 2_diff_max_tt_min_qt_intra_slice_chroma specifies the difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a chroma coding block that can be split using a ternary split and the minimum size (width or height) in luma samples of a chroma leaf block resulting from quadtree splitting of a chroma CTU with treeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I) associated with the PH. The value of ph_log 2_diff_max_tt_min_qt_intra_slice_chroma shall be in the range of 0 to CtbLog 2SizeY−MinQtLog 2SizeIntraC, inclusive. When not present, the value of ph_log 2_diff_max_tt_min_qt_intra_slice_chroma is inferred to be equal to sps_log 2 diff_max_tt_min_qt_intra_slice_chroma

ph_cu_qp_delta_subdiv_intra_slice specifies the maximum cbSubdiv value of coding units in intra slice that convey cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of ph_cu_qp_delta_subdiv_intra_slice shall be in the range of 0 to 2*(CtbLog 2SizeY−MinQtLog 2SizeIntraY+ph_max_mtt_hierarchy_depth_intra_slice_luma), inclusive. When not present, the value of ph_cu_qp_delta_subdiv_intra_slice is inferred to be equal to 0. ph_cu_chroma_qp_offset_subdiv_intra_slice specifies the maximum cbSubdiv value of coding units in intra slice that convey cu_chroma_qp_offset_flag. The value of ph_cu_chroma_qp_offset_subdiv_intra_slice shall be in the range of 0 to 2*(CtbLog 2SizeY−MinQtLog 2SizeIntraY+ph_max_mtt_hierarchy_depth_intra_slice_luma), inclusive. When not present, the value of ph_cu_chroma_qp_offset_subdiv_intra_slice is inferred to be equal to 0. ph_log 2_diff_min_qt_min_cb_inter_slice specifies the difference between the base 2 logarithm of the minimum size in luma samples of a luma leaf block resulting from quadtree splitting of a CTU and the base 2 logarithm of the minimum luma coding block size in luma samples for luma CUs in the slices with slice_type equal to 0 (B) or 1 (P) associated with the PH. The value of ph_log 2_diff_min_qt_min_cb_inter_slice shall be in the range of 0 to CtbLog 2SizeY−MinCbLog 2SizeY, inclusive. When not present, the value of ph_log_2_diff_min_qt_min_cb_luma is inferred to be equal to sps_log 2_diff_min_qt_min_cb_inter_slice. ph_max_mtt_hierarchy_depth_inter_slice specifies the maximum hierarchy depth for coding units resulting from multi-type tree splitting of a quadtree leaf in slices with slice_type equal to 0 (B) or 1 (P) associated with the PH. The value of ph_max_mtt_hierarchy_depth_inter_slice shall be in the range of 0 to 2*(CtbLog 2SizeY−MinCbLog 2SizeY), inclusive. When not present, the value of ph_max_mtt_hierarchy_depth_inter_slice is inferred to be equal to sps max Intl hierarchy depth inter slice. ph_log 2_diff_max_bt_min_qt_inter_slice specifies the difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a binary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU in the slices with slice_type equal to 0 (B) or 1 (P) associated with the PH. The value of ph_log 2_diff_max_bt_min_qt_inter_slice shall be in the range of 0 to CtbLog 2SizeY−MinQtLog 2SizeInterY, inclusive. When not present, the value of ph_log 2_diff_max_bt_min_qt_inter_slice is inferred to be equal to sps_log 2_diff_max_bt_min_qt_inter_slice. ph_log 2_diff_max_tt_min_qt_inter_slice specifies the difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a ternary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU in slices with slice_type equal to 0 (B) or 1 (P) associated with the PH. The value of ph_log 2_diff_max_tt_min_qt_inter_slice shall be in the range of 0 to CtbLog 2SizeY−MinQtLog 2SizeInterY, inclusive. When not present, the value of ph_log 2_diff_max_tt_min_qt_inter_slice is inferred to be equal to sps_log 2_diff_max_tt_min_qt_inter_slice. ph_cu_qp_delta_subdiv_inter_slice specifies the maximum cbSubdiv value of coding units that in inter slice convey cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of ph_cu_qp_delta_subdiv_inter_slice shall be in the range of 0 to 2*(CtbLog 2SizeY−MinQtLog 2SizeInterY+ph_max_mtt_hierarchy_depth_inter_slice), inclusive. When not present, the value of ph_cu_qp_delta_subdiv_inter_slice is inferred to be ph_cu_chroma_qp_offset_subdiv_inter_slice specifies the maximum cbSubdiv value of coding units in inter slice that convey cu_chroma_qp_offset_flag. The value of ph_cu_chroma_qp_offset_subdiv_inter_slice shall be in the range of 0 to 2*(CtbLog 2SizeY−MinQtLog 2SizeInterY+ph_max_mtt_hierarchy_depth_inter_slice), inclusive. When not present, the value of ph_cu_chroma_qp_offset_subdiv_inter_slice is inferred to be equal to 0. ph_temporal_mvp_enabled_flag specifies whether temporal mot ion vector predictors can be used for inter prediction for slices associated with the PH. If ph_temporal_mvp_enabled_flag is equal to 0. the syntax elements of the slices associated with the PH shall be constrained such that no temporal motion vector predictor is used in decoding of the slices. Otherwise (ph_temporal_mvp_enabled_flag is equal to 1), temporal motion vector predictors may be used in decoding of the slices associated with the PH. When not present, the value of ph_temporal_mvp_enabled_flag is inferred to be equal to 0. When no reference picture in the DPB has the same spatial resolution as the current picture, the value of ph_temporal_mvp_enabled_flag shall be equal to 0. The maximum number of subblock-based merging MVP candidates, MaxNumSubblockMergeCand, is derived as follows:

if( sps_affine_enabled flag )  MaxNumSubblockMergeCand = 5 −  five_minus_max_num_subblock_merge_cand else  MaxNumSubblockMergeCand = sps_sbtmvp_enabled_flag &&  ph_temporal_mvp_enable_flag The value of MaxNumSubblockMergeCand shall be in the range of 0 to 5, inclusive. ph_collocated_from_l0_flag equal to 1 specifies that the collocated picture used for temporal motion vector prediction is derived from reference picture list 0. ph_collocated_from_l0_flag equal to 0 specifies that the collocated picture used for temporal motion vector prediction is derived from reference picture list 1. ph_collocated_ref_idx specifies the reference index of the collocated picture used for temporal motion vector prediction. When ph_collocated_from_l0_flag is equal to 1, ph_collocated_ref_idx refers to an entry in reference picture list 0, and the value of ph_collocated_ref_idx shall be in the range of 0 to num_ref_entries[0][PicRplsIdx[0]]−1, inclusive. When ph_collocated_from_l0_flag is equal to 0, ph_collocated_ref_idx refers to an entry in reference picture list 1. and the value of ph_collocated_ref_idx shall be in the range of 0 to num_ref_entries[1][PicRplsIdx[1]]−1, inclusive. When not present, the value of ph_collocated_ref_idx is inferred to be equal to 0. mvd_l0_zero_flag equal to 1 indicates that the mvd coding(x0, y0, 1) syntax structure is not parsed and MvdL1[x0][y0][compIdx] and MvdCpL1[x0][y0][cpIdx][compIdx] are set equal to 0 for compldx=0 . . . 1 and cpIdx=0 . . . 2. mvd_l1_zero_flag equal to 0 indicates that the mvd_coding(x0, y0, 1) syntax structure is parsed. ph_fpel_mmvd_enabled_flag equal to 1 specifies that merge mode with motion vector difference uses integer sample precision in the slices associated with the PH. ph_fpel_mmvd_enabled_flag equal to 0 specifies that merge mode with motion vector difference can use fractional sample precision in the slices associated with the PH. When not present, the value of ph_fpel_nunvd_enabled_flag is inferred to be 0. ph_disable_bdof_flag equal to 1 specifies that bi-directional optical flow inter prediction based inter bi-prediction is disabled in the slices associated with the PH. ph_disable_bdof_flag equal to 0 specifies that bi-directional optical flow inter prediction based inter bi-prediction may or may not be enabled in the slices associated with the PH. When ph_disable_bdof_flag is not present, the following applies:

-   -   If sps_bdof_enabled_flag is equal to 1, the value of         ph_disable_bdof_flag is inferred to be equal to 0.     -   Otherwise (sps_bdof_enabled_flag is equal to 0), the value of         ph_disable_bdof_flag is inferred to be equal to 1.         ph_disable_dmvr_flag equal to 1 specifies that decoder motion         vector refinement based inter bi-prediction is disabled in the         slices associated with the PH. ph_disable_dmvr_flag equal to 0         specifies that decoder motion vector refinement based inter         bi-prediction may or may not be enabled in the slices associated         with the PH.         When ph_disable_dmvr_flag is not present, the following applies:     -   If sps_dmvr_enabled_flag is equal to 1, the value of         ph_disable_dmvr_flag is inferred to be equal to 0.     -   Otherwise (sps_dmvr_enabled_flag is equal to 0), the value of         ph_disable_dmvr_flag is inferred to be equal to 1         ph_disable_prof_flag equal to 1 specifies that prediction         refinement with optical flow is disabled in the slices         associated with the PH. ph_disable_prof_flag equal to 0         specifies that prediction refinement with optical flow may or         may not be enabled in the slices associated with the PH.         When ph_disable_prof_flag is not present, the following applies:     -   If sps_affine_prof_enabled_flag is equal to 1, the value of         ph_disable_prof_flag is inferred to be equal to 0.     -   Otherwise (sps affine_prof_enabled_flag is equal to 0), the         value of ph_disable_prof_flag is inferred to be equal to 1.         ph_qp_delta specifies the initial value of Qp_(Y) to be used for         the coding blocks in the picture until modified by the value of         CuQpDeltaVal in the coding unit layer.         When qp_delta_info_in_ph_flag is equal to 1, the initial value         of the Qp_(Y) quantization parameter for all slices of the         picture, SliceQp_(Y), is derived as follows:     -   SliceQp_(Y)=26+init_qp_minus26+ph_qp_delta         The value of SliceQp_(Y) shall be in the range of −QpBdOffset to         +63, inclusive.         ph_joint_cbcr_sign_flag specifies whether, in transform units         with tu_joint_cbcr_residual_flag[x0][y0] equal to 1, the         collocated residual samples of both chroma components have         inverted signs. When tu_joint_cbcr_residual_flag[x0][y0] equal         to 1 for a transform unit, ph_joint_cbcr_sign_flag equal to 0         specifies that the sign of each residual sample of the Cr (or         Cb) component is identical to the sign of the collocated Cb (or         Cr) residual sample and ph_joint_cbcr_sign_flag equal to 1         specifies that the sign of each residual sample of the Cr (or         Cb) component is given by the inverted sign of the collocated Cb         (or Cr) residual sample.         ph_sao_luma_enabled_flag equal to 1 specifies that SAO is         enabled for the luma component in all slices associated with the         PH; ph_sao_luma_enabled_flag equal to 0 specifies that SAO for         the luma component may be disabled for one, or more, or all         slices associated with the PH. When ph_sao_luma_enabled_flag is         not present, it is inferred to be         ph_sao_chroma_enabled_flag equal to 1 specifies that SAO is         enabled for the chroma component in all slices associated with         the PH; ph_sao_chroma_enabled_flag equal to 0 specifies that SAO         for chroma component may be disabled for one, or more, or all         slices associated with the PH. When ph_sao_chroma_enabled_flag         is not present, it is inferred to be equal to 0.         ph_dep_quant_enabled_flag equal to 0 specifies that dependent         quantization is disabled for the current picture.         ph_dep_quant_enabled_flag equal to 1 specifies that dependent         quantization is enabled for the current picture. When         ph_dep_quant_enabled_flag is not present, it is inferred to be         equal to 0.         pic_sign_data_hiding_enabled_flag equal to 0 specifies that sign         bit hiding is disabled for the current picture.         pic_sign_data_hiding_enabled_flag equal to 1 specifies that sign         bit hiding is enabled for the current picture. When         pic_sign_data_hiding_enabled_flag is not present, it is inferred         to be equal to 0.         ph_deblocking_filter_override_flag equal to 1 specifies that         deblocking parameters are present in the PH.         ph_deblocking_filter_override_flag equal to 0 specifies that         deblocking parameters are not present in the PH. When not         present, the value of ph_deblocking_filter_override_flag is         inferred to be equal to 0.         ph_deblocking_filter_disabled_flag equal to 1 specifies that the         operation of the deblocking filter is not applied for the slices         associated with the PH. ph_deblocking_filter_disabled_flag equal         to 0 specifies that the operation of the deblocking filler is         applied for the slices associated with the PH. When         ph_deblocking_filter_disabled_flag is not present, it is         inferred to be equal to pps_deblocking_filter_disabled_flag.         ph_beta_offset_div2 and ph_tc_offset_div2 specify the deblocking         parameter offsets for β and tC (divided by 2) that are applied         to the luma component for the slices associated with the PH. The         values of ph_beta_offset_div2 and ph_tc_offset_div2 shall both         be in the range of −12 to 12, inclusive. When not present. the         values of ph_beta_offset_div2 and ph_tc_offset_div2 are inferred         to be equal to pps_beta_offset_div2 and pps_tc_offset_div2,         respectively.         ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 specify the         deblocking parameter offsets for p and tC (divided by 2) that         are applied to the Cb component for the slices associated with         the PH. The values of ph_cb_beta_offset_div2 and         ph_cb_tc_offset_div2 shall both be in the range of −12 to 12,         inclusive. When not present, the values of         ph_cb_bela_offsel_div2 and ph_cb_tc_offset_div2 are inferred to         be equal to pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2,         respectively.         ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 specify the         deblocking parameter offsets for β and tC (divided by 2) that         are applied to the Cr component for the slices associated with         the PH. The values of ph_cr_beta_offset_div2 and         ph_cr_tc_offset_div2 shall both be in the range of −12 to 12,         inclusive. When not present, the values of         ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 are inferred to         be equal to pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2,         respectively.         ph_extension_length specifies the length of the PH extension         data in bytes, not including the bits used for signalling         ph_extension_length itself. The value of ph_extension_length         shall be in the range of 0 to 256, inclusive. When not present,         the value of ph_extension_length is inferred to be equal to 0.         ph_extension_data_byte may have any value. Decoders conforming         to this version of this Specification shall ignore the value of         ph_extension_data_byte. Its value does not affect decoder         conformance to profiles specified in this version of         specification.

As provided in Table 2, a NAL unit may include coded slices of pictures. A slice syntax structure includes slice header( ) syntax structure and a slice data( ) syntax structure. Table 6 illustrates the syntax of the slice header provided in JVET-Q2001.

TABLE 6 De- scrip- tor slice_header( ) {  picture_header_in_slice_header_flag u(1)  if( picture_header_in_slice_header_flag )   picture_header_structure( )  if( subpic_info_present_flag )   slice_subpic_id u(v)  if( ( rect_slice_flag && NumSlicesInSubpic[  CurrSubpicIdx ] > 1 ) | |    ( !rect_slice_flag && NumTilesInPic > 1 ) )   slice_address u(v)     for( i = 0; i < NumExtraShBits; i++ )   sh_extra_bit[ i ] u(1)  if( !rect_slice_flag && NumTilesInPic > 1 )   num_tiles_in_slice_minus1 ue(v)  if( ph_inter_slice_allowed_flag )   slice_type ue(v)  if( sps_alf_enabled_flag && !alf_info_in_ph_flag ) {   slice_alf_enabled_flag u(1)   if( slice_alf_enabled_flag ) {    slice_num_alf_aps_ids_luma u(3)    for( i = 0; i < slice_num_alf_aps_ids_luma; i++ )     slice_alf_aps_id_luma[ i ] u(3)    if( ChromaArrayType != 0 )     slice_alf_chroma_idc u(2)    if( slice_alf_chroma_idc )     slice_alf_aps_id_chroma u(3)    if( sps_ccalf_enabled_flag ) {     slice_cc_alf_cb_enabled_flag u(1)     if( slice_cc_alf_cb_enabled_flag )      slice_cc_alf_cb_aps_id u(3)     slice_cc_alf_cr_enabled_flag u(1)     if( slice_cc_alf_cr_enabled_flag )      slice_cc_alf_cr_aps_id u(3)    }   }  }  if( separate_colour_plane_flag = = 1 )   colour_plane_id u(2)  if( !rpl_info_in_ph_flag && ( ( nal_unit_type !=  IDR_W_RADL && nal_unit_type !=    IDR_N_LP ) | | sps_idr_rpl_present_flag ) )   ref_pic_lists( )  if( ( rpl_info_in_ph_flag | | ( ( nal_unit_type !=  IDR_W_RADL && nal_unit_ type !=    IDR_N_LP ) | | sps_idr_rpl_present_flag ) ) &&    ( slice_type != I && num_ref_entries[ 0 ][ RplsIdx[    0 ] ] > 1 ) | |    ( slice_type = = B && num_ref_entries[ 1 ][ RplsIdx[    1 ] ] > 1 ) ) {   num_ref_idx_active_override_flag u(1)   if( num_ref_idx_active_override_flag )    for( i = 0; i < ( slice_type = = B ? 2: 1 ); i++ )     if( num_ref_entries[ i ][ RplsIdx[ i ] ] > 1 )      num_ref_idx_active_minus1[ i ] ue(v)  }  if( slice_type != I ) {   if( cabac_init_present_flag )    cabac_init_flag u(1)   if( ph_temporal_mvp_enabled_flag &&   !rpl_info_in_ph_flag ) {    if( slice_type = = B )     slice_collocated_from_l0_flag u(1)    if( ( slice_collocated_from_l0_flag &&    NumRefIdxActive[ 0 ] > 1 ) | |      ( ! slice_collocated_from_l0_flag &&      NumRefIdxActive[ 1 ] > 1 ) )     slice_collocated_ref_idx ue(v)   }   if( !wp_info_in_ph_flag && ( ( pps_weighted_pred_flag   && slice_type = = P ) | |     ( pps_weighted_bipred_flag && slice_type = = B ) ) )    pred_weight_table( )  }  if( !qp_delta_info_in_ph_flag )   slice_qp_delta se(v)  if( pps_slice_chroma_qp_offsets_present_flag ) {   slice_cb_qp_offset se(v)   slice_cr_qp_offset se(v)   if( sps_joint_cbcr_enabled_flag )    slice_joint_cbcr_qp_offset se(v)  }  if( pps_cu_chroma_qp_offset_list_enabled_flag )   cu_chroma_qp_offset_enabled_flag u(1)  if( sps_sao_enabled_flag && !sao_info_in_ph_flag ) {   slice_sao_luma_flag u(1)   if( ChromaArrayType != 0 )    slice_sao_chroma_flag u(1)  }  if( deblocking_filter_override_enabled_flag &&  !dbf_info_in_ph_flag )   slice_deblocking_filter_override_flag u(1)  if( slice_deblocking_filter_override_flag ) {   slice_deblocking_filter_disabled_flag u(1)   if( !slice_deblocking_filter_disabled_flag ) {    slice_beta_offset_div2 se(v)    slice_tc_offset_div2 se(v)    slice_cb_beta_offset_div2 se(v)    slice_cb_tc_offset_div2 se(v)    slice_cr_beta_offset_div2 se(v)    slice_cr_tc_offset_div2 se(v)   }  }  slice_ts_residual_coding_disabled_flag u(1)  if( ph_lmcs_enabled_flag )   slice_lmcs_enabled_flag u(1)  if( ph_scaling_list_enabled_flag )   slice_scaling_list_present_flag u(1)  if( NumEntryPoints > 0 ) {   offset_len_minus1 ue(v)   for( i = 0; i < NumEntryPoints; i++ )    entry_point_offset_minus1[ i ] u(v)  }  if( slice_header_extension_present_flag ) {   slice_header_extension_length ue(v)   for( i = 0; i < slice_header_extension_length; i++)    slice_header_extension_data_byte[ i ] u(8)  }  byte_alignment( ) }

With respect to Table 6, JVET-Q2001 provides the following semantics:

The variable CuQpDeltaVal, specifying the difference between a luma quantization parameter for the coding unit containing cu_qp_delta_abs and its prediction, is set equal to 0. The variables CuQpOffset_(Cb), CuQpOffset_(Cr), and CuQpOffset_(CbCr), specifying values to be used when determining the respective values of the Qp′_(Cb), Qp′_(Cr), and Qp′_(CbCr) quantization parameters for the coding unit containing cu_chroma_qp_offset_flag, are all set equal to 0.

picture_header_in_slice_header_flag equal to 1 specifies that the PH syntax structure is present in the slice header. picture_header_in_slice_header_flag equal to 0 specifies that the PH syntax structure is not present in the slice header.

It is a requirement of bitstream conformance that the value of picture_header_in_slice_header_flag shall be the same in all coded slices in a CLVS.

When picture_header_in_slice_header_flag is equal to 1 for a coded slice, it is a requirement of bitstream conformance that no VCL NAL unit with nal_unit_type equal to PH_NUT shall be present in the CLVS.

When picture_header_in_slice_header_flag is equal to 0, all coded slices in the current picture shall have picture_header_in_slice_header_flag is equal to 0, and the current PU shall have a PH NAL unit.

slice_subpic_id specifies the subpicture ID of the subpicture that contains the slice. If slice_subpic_id is present, the value of the variable CurrSubpicIdx is derived to be such that SubpicIdVal[CurrSubpicIdx] is equal to slice_subpic_id. Otherwise (slice_subpic_id is not present). CurrSubpicIdx is derived to be equal to 0. The length of slice_subpic_id is sps_subpic_id_len_minus1+1 bits. slice_address specifies the slice address of the slice. When not present, the value of slice_address is inferred to be equal to 0. When rect_slice_flag is equal to 1 and NumSlicesInSubpic[CurrSubpicIdx] is equal to 1, the value of slice_address is inferred to be equal to 0.

If rect_slice_flag is equal to 0, the following applies:

-   -   The slice address is the raster scan tile index.     -   The length of slice_address is Ceil(Log 2 (NumTilesInPic)) bits.     -   The value of slice_address shall be in the range of 0 to         NumTilesInPic−1, inclusive.

Otherwise (rect_slice_flag is equal to 1), the following applies:

-   -   The slice address is the subpicture-level slice index of the         slice.     -   The length of slice_address is Ceil(Log         2(NumSlicesInSubpic[CurrSubpicIdx])) bits.     -   The value of slice_address shall be in the range of 0 to         NumSlicesInSubpic[CurrSubpicIdx]−1, inclusive.

It is a requirement of bitstream conformance that the following constraints apply:

-   -   If rect_slice_flag is equal to 0 or subpic_info_present_flag is         equal to 0, the value of slice_address shall not be equal to the         value of slice_address of any other coded slice NAL unit of the         same coded picture.     -   Otherwise, the pair of slice_subpic_id and slice_address values         shall not be equal to the pair of slice_subpic_id and         slice_address values of any other coded slice NAL unit of the         same coded picture.     -   The shapes of the slices of a picture shall be such that each         CTU, when decoded, shall have its entire left boundary and         entire top boundary consisting of a picture boundary or         consisting of boundaries of previously decoded CTU(s).         sh_extra_bit[i] may be equal to 1 or 0. Decoders conforming to         this version of this Specification shall ignore the value of         sh_extra_bit[i]. Its value does not affect decoder conformance         to profiles specified in this version of specification.         num_tiles_in_slice_minus1 plus 1, when present, specifies the         number of tiles in the slice. The value of num tiles in slice         minus1 shall be in the range of 0 to NumTilesInPic−1, inclusive.         The variable NumCtusInCurrSlice, which specifies the number of         CTUs in the current slice, and the list CtbAddrinCurrSlice[i],         for i ranging from 0 to NumCtusInCurrSlice−1, inclusive,         specifying the picture raster scan address of the i-th CTB         within the slice, are derived as follows:

if( rect_slice_flag ) {  picLevelSliceIdx = slice_address  for( j = 0; j < CurrSubpicIdx; j++ )   picLevelSliceIdx += NumSlicesInSubpic[ j ]  NumCtusInCurrSlice = NumCtusInSlice[ picLevelSliceIdx ]  for( i = 0; i < NumCtusInCurrSlice; i++ )   CtbAddrInCurrSlice[ i ] = CtbAddrInSlice[   picLevelSliceIdx ][ i ] } else {  NumCtusInCurrSlice = 0  for( tileIdx = slice_address; tileIdx <= slice_address +  num_tiles_in_slice_minus1; tileIdx++ ) {   tileX = tileIdx % NumTileColumns   tileY = tileIdx / NumTileColumns   for( ctbY = tileRowBd[ tileY ]; ctbY < tileRowBd[ tileY + 1 ];   ctbY++ ) {    for( ctbX = tileColBd[ tileX ]; ctbX < tileColBd[ tileX + 1 ];    ctbX++ ) {     CtbAddrInCurrSlice[ NumCtusInCurrSlice ] =     ctbY * PicWidthInCtb + ctbX     NumCtusInCurrSlice++    }   }  } } The variables SubpicLeftBoundaryPos, SubpicTopBoundaryPos, SubpicRightBoundaryPos, and SubpicBotBoundaryPos are derived as follows:

if( subpic_treated_as_pic_flag[ CurrSubpicIdx ] ) {  SubpicLeftBoundaryPos = subpic_ctu_top_left_x[  CurrSubpicIdx ] * CtbSizeY  SubpicRightBoundaryPos = Min(  pic_width_max_in_luma_samples − 1,   ( subpic_ctu_top_left_x[ CurrSubpicIdx ] +   subpic_width_minus1[ CurrSubpicIdx ] + 1 ) * CtbSizeY − 1 )  SubpicTopBoundaryPos = subpic_ctu_top_left_y[  CurrSubpicIdx ] *CtbSizeY (118)  SubpicBotBoundaryPos = Min(  pic_height_max_in_luma_samples − 1,   ( subpic_ctu_top_left_y[ CurrSubpicIdx ] +   subpic_height_minus1[ CurrSubpicIdx ] + 1 ) * CtbSizeY − 1 ) } slice_type specifies the coding type of the slice according to Table 7.

TABLE 7 slice_type Name of slice_type 0 B (B slice) 1 P (P slice) 2 I (I slice) When not present, the value of slice_type is inferred to be equal to 2. When ph_intra_slice_allowed_flag is equal to 0. the value of slice_type shall be equal to 0 or 1. When nal_unit_type is in the range of IDR_W_RADL to CRA_NUT, inclusive, and vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is equal to 1, slice_type shall be equal to 2. The variables MinQtLog 2SizeY, MinQtLog 2SizeC, MinQtSizeY, MinQtSizeC, MaxBtSizeY, MaxBtSizeC, MinBtSizeY, MaxTtSizeY, MaxTtSizeC, MinTtSizeY, MaxMttDepthY and MaxMttDepthC are derived as follows:

-   -   If slice_type equal to 2 (I),         -   MinQtLog 2SizeY=MinCbLog 2SizeY+ph_log             2_diff_min_qt_min_cb_intra_slice_luma         -   MinQtLog 2SizeC=MinCbLog 2SizeY+ph_log             2_diff_min_qt_min_cb_intra_slice_chroma         -   MaxBtSizeY=1<<(MinQtLog 2SizeY+ph_log             2_diff_max_bt_min_qt_intra_slice_luma)         -   MaxBtSizeC=1<<(MinQtLog 2SizeC+ph_log             2_diff_max_bt_min_qt_intra_slice_chroma)         -   MaxTtSizeY=1<<(MinQtLog 2SizeY+ph_log             2_diff_max_tt_min_qt_intra_slice_luma)         -   MaxTtSizeC=1<<(MinQtLog 2SizeC+ph_log             2_diff_max_tt_min_qt_intra_slice_chroma)         -   MaxMttDepthY=ph_max_mtt_hierarchy_depth_intra_slice_luma         -   MaxMttDepthC=ph_max_mtt_hierarchy_depth_intra_slice_chroma         -   CuQpDeltaSubdiv=ph_cu_qp_delta_subdiv_intra_slice         -   CuChromaQpOffsctSubdiv=ph_cu_chroma_qp_offset_subdiv_intra_slice     -   Otherwise (slice_type equal to 0 (B) or 1 (P)),         -   MinQtLog 2SizeY=MinCbLog 2SizeY+ph_log             2_diff_min_qt_min_cb_inter_slice         -   MinQtLog 2SizeC=MinCbLog 2SizeY+ph_log             2_diff_min_qt_min_cb_inter_slice)         -   MaxBtSizeY=1<<(MinQtLog 2SizeY+ph_log             2_diff_max_bt_min_qt_inter_slice)         -   MaxBtSizeC=1<<(MinQtLog 2SizeC+ph_log             2_diff_max_bt_min_qt_inter_slice)         -   MaxTtSizeY=1<<(MinQtLog 2SizeY+ph_log             2_diff_max_tt_min_qt_inter_slice)         -   MaxTtSizeC=1<<(MinQtLog 2SizeC+ph_log             2_diff_max_tt_min_qt_inter_slice)         -   MaxMaDepthY=ph_max_mit_hierarchy_depth_inter_slice         -   MaxMttDepthC=ph_max_mtt_hierarchy_depth_inter_slice         -   CuQpDeltaSubdiv=ph_cu_qp_delta_subdiv_inter_slice         -   CuChromaQpOffsetSubdiv=ph_cu_chroma_qp_offset_subdiv_inter_slice     -   MinQtSizeY=1<<MinQtLog 2SizeY     -   MinQtSizeC=1<<MinQtLog 2SizeC     -   MinBtSizeY=1<<MinCbLog 2SizeY     -   MinQtSizeY=1<<MinCbLog 2SizeY         slice_alf_enabled_flag equal to 1 specifies that adaptive loop         filter is enabled and may be applied to Y, Cb, or Cr colour         component in a slice. slice_alf_enabled_flag equal to 0         specifies that adaptive loop filter is disabled for all colour         components in a slice. When not present, the value of         slice_alf_enabled_flag is inferred to be equal to         ph_alf_enabled_flag.         slice_num_alf_aps_ids_luma specifies the number of ALF APSs that         the slice refers to. When slice_alf_enabled_flag is equal to 1         and slice_num_alf_aps_ids_luma is not present, the value of         slice_num_alf_aps_ids_luma is inferred to be equal to the value         of ph_num_alf_aps_ids_luma.         slice_alf_aps_id_luma[i] specifies the         adaptation_parameter_set_id of the i-th ALF APS that the luma         component of the slice refers to. The Temporand of the APS NAL         unit having aps_params_type equal to ALF_APS and         adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i]         shall be less than or equal to the Temporand of the coded slice         NAL unit. When slice_alf_enabled_flag is equal to 1 and slice         alf_aps_id_luma[i] is not present, the value of         slice_alf_aps_id_luma[i] is inferred to be equal to the value of         ph_alf_aps_id_luma[i]. The value of alf_luma_filter_signal_flag         of the APS NAL unit having aps_params_type equal to ALF APS and         adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i]         shall be equal to 1.         slice_alf_chruma_idc equal to 0 specifies that the adaptive loop         filter is not applied to Cb and Cr colour components.         slice_alf_chroma_idc equal to 1 indicates that the adaptive loop         filter is applied to the Cb colour component.         slice_alf_chroma_idc equal to 2 indicates that the adaptive loop         filter is applied to the Cr colour component.         slice_alf_chroma_idc equal to 3 indicates that the adaptive loop         filter is applied to Cb and Cr colour components. When         slice_alf_chroma_idc is not present, it is inferred to be equal         to ph_alf_chroma_idc.         slice_alf_aps_id_chroma specifies the         adaptation_parameter_set_id of the ALF APS that the chroma         component of the slice refers to. The TemporalId of the APS NAL         unit having aps_params_type equal to ALF_APS and         adaptation_parameter_set_id equal to slice_alf_aps_id_chroma         shall be less than or equal to the TemporalId of the coded slice         NAL unit. When slice_alf_enabled_flag is equal to 1 and         slice_alf_aps_id_chroma is not present, the value of         slice_alf_aps_id_chroma is inferred to be equal to the value of         ph_alf_aps_id_chroma.         The value of alf_chroma_filter_signal_flag of the APS NAL unit         having aps_params_type equal to ALF_APS and         adaptation_parameter_set_id equal to slice alf_aps_id_chroma         shall be equal to 1.         slice_cc_alf_cb_enabled_flag equal to 0 specifies that the         cross-component filter is not applied to the Cb colour         component. slice_cc_alf_cb_enabled_flag equal to 1 indicates         that the cross-component filter is enabled and may be applied to         the Cb colour component. When slice_cc_alf_cb_enabled_flag is         not present, it is inferred to be equal to         ph_cc_alf_cb_enabled_flag.         slice_cc_alf_cb_aps_id specifics the adaptation_parameter_set_id         that the Cb colour component of the slice refers to. The         TemporalId of the APS NAL unit having aps_params_type equal to         ALF_APS and adaptation_parameter_set_id equal to         slice_cc_alf_cb_aps_id shall be less than or equal to the         TemporalId of the coded slice NAL unit. When         slice_cc_alf_cb_enabled_flag is equal to 1 and         slice_cc_alf_cb_aps_id is not present, the value of         slice_cc_alf_cb_aps_id is inferred to be equal to the value of         ph_cc_alf_cb_aps_id.         The value of alf_cc_cb_filter_signal_flag of the APS NAL unit         having aps_params_type equal to ALF_APS and         adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id         shall be equal to 1.         slice_cc_alf_cr_enabled_flag equal to 0 specifies that the         cross-component filter is not applied to the Cr colour         component. slice_cc_alf_cb_enabled_flag equal to 1 indicates         that the cross-component adaptive loop filter is enabled and may         be applied to the Cr colour component. When         slice_cc_alf_cr_enabled_flag is not present, it is inferred to         be equal to ph_cc_alf_cr_enabled_flag.         slice_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id         that the Cr colour component of the slice refers to. The         TemporalId of the APS NAL unit having aps_params_type equal to         ALF APS and adaptation_parameter_set_id equal to         slice_cc_alf_cr_aps_id shall be less than or equal to the         TemporalId of the coded slice NAL unit. When         slice_cc_alf_cr_enabled_flag is equal to 1 and         slice_cc_alf_cr_aps_id is not present, the value of         slice_cc_alf_cr_aps_id is inferred to be equal to the value of         ph_cc_alf_cr_aps_id.         The value of alf_cc_cr_filter_signal_flag of the APS NAL unit         having aps_params_type equal to ALF_APS and         adaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id         shall be equal to 1.         colour_plane_id identifies the colour plane associated with the         current slice when separate_colour_plane_flag is equal to 1. The         value of colour_plane_id shall be in the range of 0 to 2,         inclusive. colour_plane_id values 0, 1 and 2 correspond to the         Y, Cb and Cr planes, respectively. The value 3 of         colour_plane_id is reserved for future use by ITU-T|ISO/IEC.

NOTE—There is no dependency between the decoding processes of different colour planes of one picture.

num_ref_id_x_active_override_flag equal to 1 specifies that the syntax element num_ref_idx_active_minus1[0] is present for P and B slices and the syntax element num_ref_idx_active_minus1[1] is present for B slices. num_ref_idx_active_override_flag equal to 0 specifies that the syntax elements num_ref_idx_active_minus1[0] and num_ref_idx_active_minus1[1] are not present. When not present, the value of num_ref_idx_active_override_flag is inferred to be equal to 1. num_ref_idx_active_minus1 [i] is used for the derivation of the variable NumRefIdxActive[i] as specified. The value of num_ref_idx_active_minus1[i] shall be in the range of 0 to 14, inclusive. For i equal to 0 or 1, when the current slice is a B slice, num_ref_idx_active_override_flag is equal to 1, and num ref_idx_active_minus1[i] is not present, num_ref_idx_active_minus1[i] is inferred to be equal to 0. When the current slice is a P slice, num_ref_idx_active_override_flag is equal to 1, and num_ref_idx_active_minus1[0] is not present, num_ref_idx_active_minus1[0] is inferred to be equal to 0. The variable NumRefIdxActive[i] is derived as follows:

for( i = 0; i < 2; i++ ) {  if( slice_type = = B | | ( slice_type = = P && i = = 0 ) ) {   if( num_ref_idx_active_override_flag )    NumRefIdxActive[ i ] = num_ref_idx_active_minus1[ i ] + 1   else {    if( num_ref_entries[ i ][ RplsIdx[ i ] ] >=    num_ref_idx_default_active_minus1[ i ] + 1 )     NumRefIdxActive[ i ] =     num_ref_idx_default_active_minus1[ i ] + 1    else     NumRefIdxActive[ i ] = num_ref_entries[ i ][ RplsIdx[ i ] ]   }  } else /* slice_type = = I | | ( slice_type = = P && i = = 1 ) */   NumRefIdxActive[ i ] = 0 } The value of NumRefIdxActive[i]−1 specifies the maximum reference index for reference picture list i that may be used to decode the slice. When the value of NumRefIdxActive[i] is equal to 0. no reference index for reference picture list i may be used to decode the slice. When the current slice is a P slice, the value of NumRefIdxActive[0] shall be greater than 0. When the current slice is a B slice, both NumRefIdxActive[0] and NumRefIdxActive[1] shall be greater than 0. cabac_init_flag specifies the method for determining the initialization table used in the initialization process for context variables. When cabac_init_flag is not present, it is inferred to be equal to 0.

slice_collocated_from_l0_flag equal to 1 specifies that the collocated picture used for temporal motion vector prediction is derived from reference picture list 0. slice_collocated_from_l0_flag equal to 0 specifies that the collocated picture used for temporal motion vector prediction is derived from reference picture list 1.

When slice type is equal to B or P, ph_temporal_mvp_enabled_flag is equal to 1, and slice_collocated_from_l0_flag is not present, the following applies:

-   -   If rpl_info_in_ph_flag is equal to 1,         slice_collocated_from_l0_flag is inferred to be equal to         ph_collocated_from_l0_flag.     -   Otherwise (rpl_info_in_ph_flag is equal to 0 and if slice_type         is equal to P, the value of slice_collocated_from_l0_flag is         inferred to be equal to 1.         slice_collocated_ref_idx specifies the reference index of the         collocated picture used for temporal motion vector prediction.         When slice_type is equal to P or when slice_type is equal to B         and collocated_from_l0_flag is equal to 1,         slice_collocated_ref_idx refers to an entry in reference picture         list 0, and the value of slice_collocated_ref_idx shall be in         the range of 0 to NumRefIdxActive[0]-1, inclusive.         When slice_type is equal to B and slice_collocated_from_l0_flag         is equal to 0, slice_collocated_ref_idx refers to an entry in         reference picture list 1, and the value of         slice_collocated_ref_idx shall be in the range of 0 to         NumRefIdxActive[1]−1−1, inclusive.         When slice collocated ref_idx is not present, the following         applies:     -   If rpl_info_in_ph_flag is equal to 1, the value of         slice_collocated_ref_idx is inferred to be equal to         ph_collocated_ref_idx.     -   Otherwise (rpl_info_in_ph_flag is equal to 0), the value of         slice_collocated_ref_idx is inferred to be equal to 0.

It is a requirement of bitstream conformance that the picture referred to by slice_collocated_ref_idx shall be the same for all slices of a coded picture.

It is a requirement of bitstream conformance that the values of pic_width_in_luma_samples and pic_height_in_luma_samples of the reference picture referred to by slice_collocated_ref_idx shall be equal to the values of pic_width_in_luma_samples and pic_height_in_luma_samples, respectively. of the current picture. and RprConstraintsActive[slice_collocated_from_l0_flag ? 0:1][slice_collocated_ref_idx] shall be equal to 0.

slice_qp_delta specifies the initial value of Qp_(Y) to be used for the coding blocks in the slice until modified by the value of CuQpDeltaVal in the coding unit layer. When qp_delta_info_in_ph_flag is equal to 0, the initial value of the Qp_(Y) quantization parameter for the slice, SliceQp_(Y), is derived as follows:

-   -   SliceQp_(Y)=26+init_qp_minus26+slice_qp_delta         The value of SliceQp_(Y) shall be in the range of −QpBdOffset to         +63, inclusive.

When either of the following conditions is true:

-   -   The value of wp_info_in_ph_flag is equal to 1,         pps_weighted_pred_flag is equal to 1, and slice_type is equal to         P.     -   The value of wp_info_in_ph_flag is equal to 1,         pps_weighted_bipred_flag is equal to 1, and slice_type is equal         to B.         the following applies:     -   The value of NumRefIdxActive[0] shall be less than or equal to         the value of NumWeightsL0.     -   For each reference picture index RefPicList[0][i] for i in the         range of 0 to NumRefIdxActive[0]-1, inclusive, the luma weight,         Cb weight, and Cr weight that apply to the reference picture         index are LumaWeightL0[i], ChromaWeightL0[0][i], and         ChromaWeightL0[1][i], respectively.         When wp_info_in_ph_flag is equal to 1, pps_weighted_bipred_flag         is equal to 1, and slice_type is equal to B, the following         applies:     -   The value of NumRefIdxActive[1] shall be less than or equal to         the value of NumWeightsL1.     -   For each reference picture index RefPicList[1][i] for i in the         range of 0 to NumRefIdxActive[1-1, inclusive, the luma weight,         Cb weight, and Cr weight that apply to the reference picture         index are Luma WeightL1[i], Chroma WeightL1[0 [i], and         ChromaWeightL1]1][i], respectively.         slice_ch_qp_offset specifies a difference to be added to the         value of pps_cb_qp_offset when determining the value of the         Qp′_(Cb) quantization parameter. The value of slice_cb_qp_offset         shall be in the range of −12 to +12, inclusive. When         slice_cb_qp_offset is not present, it is inferred to be equal         to 0. The value of pps_cb_qp_offset+slice_cb_qp_offset shall be         in the range of −12 to +12, inclusive.         slice_cr_qp_offset specifies a difference to be added to the         value of pps_cr_qp_offset when determining the value of the Op′         or quantization parameter. The value of slice_cr_qp_offset shall         be in the range of −12 to +12, inclusive. When         slice_cr_qp_offset is not present, it is inferred to be equal         to 0. The value of pps_cr_qp_offset+slice_cr_qp_offset shall be         in the range of −12 to +12, inclusive.         slice joint_cbcr_qp_offset specifies a difference to be added to         the value of pps_joint_cbcr_qp_offset value when determining the         value of the Qp′_(CbCr), The value of slice_joint_cbcr_qp_offset         shall be in the range of −12 to +12, inclusive. When         slice_joint_cbcr_qp_offset is not present, it is inferred to be         equal to 0. The value of         pps_joint_cbcr_qp_offset_value+slice_joint_cbcr_qp_offset shall         be in the range of −12 to +12, inclusive.         cu_chroma_qp_offset_enabled_flag equal to 1 specifies that the         cu_chroma_qp_offset_flag may be present in the transform unit         and palette coding syntax. cu_chroma_qp_offset_enabled_flag         equal to 0 specifies that the cu_chroma_qp_offset_flag is not         present in the transform unit or palette coding syntax. When not         present, the value of cu_chroma_qp_offset_enabled_flag is         inferred to be equal to 0.         slice_sao_luma_flag equal to 1 specifies that SAO is enabled for         the luma component in the current slice; slice_sao_luma_flag         equal to 0 specifics that SAO is disabled for the luma component         in the current slice. When slice_sao_luma_flag is not present,         it is inferred to be equal to ph_sao_luma_enabled_flag.         slice_sao_chroma_flag equal to 1 specifies that SAO is enabled         for the chroma component in the current slice;         slice_sao_chroma_flag equal to 0 specifies that SAO is disabled         for the chroma component in the current slice. When         slice_sao_chroma_flag is not present, it is inferred to be equal         to ph_sao_chroma_enabled_flag.         slice_deblocking_filter_override_flag equal to 1 specifies that         deblocking parameters are present in the slice header.         slice_deblocking_filter_override_flag equal to 0 specifies that         deblocking parameters are not present in the slice header. When         not present, the value of slice_deblocking_filter_override_flag         is inferred to be equal to ph_deblocking_filter_override_flag.         slice_deblocking_filter_disabled_flag equal to 1 specifies that         the operation of the deblocking filter is not applied for the         current slice. slice_deblocking_filter_disabled_flag equal to 0         specifies that the operation of the deblocking filter is applied         for the current slice. When         slice_deblocking_fllter_disabled_flag is not present, it is         inferred to be equal to ph_deblocking_filter_disabled_flag.         slice_beta_offset_div2 and slice_tc_offset_div2 specify the         deblocking parameter offsets for and tC (divided by 2) that are         applied to the luma component for the current slice. The values         of slice_beta_offset_div2 and slice_tc_offset_div2 shall both be         in the range of −12 to 12, inclusive. When not present, the         values of slice_beta_offset_div2 and slice_tc_offset_div2 are         inferred lobe equal to ph_beta_offset_div2 and         ph_tc_offset_div2, respectively.         slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify         the deblocking parameter offsets for β and tC (divided by 2)         that are applied to the Cb component for the current slice. The         values of slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2         shall both be in the range of −12 to 12, inclusive. When not         present. the values of slice_cb_beta_offset_div2 and         slice_cb_tc_offset_div2 are inferred to be equal to         ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2, respectively.         slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify         the deblocking parameter offsets for β and tC (divided by 2)         that are applied to the Cr component for the current slice. The         values of slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2         shall both be in the range of −12 to 12, inclusive. When not         present, the values of slice_cr_beta_offset_div2 and         slice_cr_tc_offset_div2 are inferred to be equal to         ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2, respectively.         slice_ts_residual_coding_disabled_flag equal to 1 specifies that         the residual_coding( ) syntax structure is used to parse the         residual samples of a transform skip block for the current         slice. slice_ts_residual_coding_disabled_flag equal to 0         specifies that the residual_ts_coding( ) syntax structure is         used to parse the residual samples of a transform skip block for         the current slice. When slice_ts_residual_coding_disabled_flag         is not present, it is inferred to be equal to 0.         slice_lmcs_enabled_flag equal to 1 specifies that luma mapping         with chroma scaling is enabled for the current slice.         slice_lmcs_enabled_flag equal to 0 specifies that luma mapping         with chroma scaling is not enabled for the current slice. When         slice_lmcs_enabled_flag is not present, it is inferred to be         equal to 0.         slice_scaling_list_present_flag equal to 1 specifies that the         scaling list data used for the current slice is derived based on         the scaling list data contained in the referenced scaling list         APS with aps_params_type equal to SCALING_APS and         adaptation_parameter_set_id equal to ph_scaling_list_aps_id.         slice_scaling_list_present_flag equal to 0 specifies that the         scaling list data used for the current picture is the default         scaling list data derived as specified. When not present, the         value of slice_scaling_list_present_flag is inferred to be equal         to 0.         The variable NumEntryPoints, which specifies the number of entry         points in the current slice, is derived as follows:

NumEntryPoints = 0 for( i = 1; i < NumCtusInCurrSlice; i++ ) {  ctbAddrX = CtbAddrInCurrSlice[ i ] % PicWidthInCtbsY  ctbAddrY = CtbAddrInCurrSlice[ i ] / PicWidthInCtbsY  (145) prevCtbAddrX = CtbAddrInCurrSlice[ i − 1 ] % PicWidthInCtbsY  prevCtbAddrY = CtbAddrInCurrSlice[ i − 1 ] / PicWidthInCtbsY  if( CtbToTileRowBd[ ctbAddrY ] != CtbToTileRowBd[  prevCtbAddrY ] | |    CtbToTileColBd[ ctbAddrX ] != CtbToTileColBd[    prevCtbAddrX ] | |    ( ctbAddrY != prevCtbAddrY &&    sps_entry_point_offsets_present_flag ) )   NumEntryPoints++ } offset_len_minus1 plus 1 specifies the length, in bits, of the entrypoint offset minus1|[i|] syntax elements. The value of offset_len_minus1 shall be in the range of 0 to 31, inclusive. entry_point_offset_minus1[i] plus 1 specifies the i-th entry point offset in bytes, and is represented by offset_len_minus1 plus 1 bits. The slice data that follow the slice header consists of NumEntryPoints+1 subsets, with subset index values ranging from 0 to NumEntryPoints, inclusive. The first byte of the slice data is considered byte 0. When present, emulation prevention bytes that appear in the slice data portion of the coded slice NAL unit are counted as part of the slice data for purposes of subset identification. Subset 0 consists of bytes 0 to entry_point_offset_minus1[0], inclusive, of the coded slice data, subset k, with k in the range of 1 to NumEntryPoints−1, inclusive, consists of bytes firstByte[k] to lastByte[k], inclusive, of the coded slice data with firstByte[k] and lastByte[k] defined as:

-   -   firstByte[k]=(entry_point_offset_minus1[n−1]+1)     -   lastByte[k]=firstByte[k]+entry_point_offset_minus1[k]         The last subset (with subset index equal to NumEntryPoints)         consists of the remaining bytes of the coded slice data.         When sps_entropy_coding_sync_enabled_flag is equal to 0 and the         slice contains one or more complete tiles, each subset shall         consist of all coded bits of all CTUs in the slice that are         within the same tile, and the number of subsets (i.e., the value         of NumEntryPoints+1) shall be equal to the number of tiles in         the slice.

When sps_entropy_coding_sync_enabled_flag is equal to 0 and the slice contains a subset of CTU rows from a single tile, the NumEntryPoints shall be 0, and the number of subsets shall be 1. The subset shall consist of all coded bits of all CTUs in the slice. When sps_entropy_coding_sync_enabled_flag is equal to 1, each subset k with k in the range of 0 to NumEntryPoints, inclusive, shall consist of all coded bits of all CTUs in a CTU row within a tile, and the number of subsets (i.e., the value of NumEntryPoints+1) shall be equal to the total number of tile-specific CTU rows in the slice.

slice_header_extension_length specifies the length of the slice header extension data in bytes, not including the bits used for signalling slice_header_extension_length itself. The value of slice_header_extension_length shall be in the range of 0 to 256, inclusive. When not present, the value of slice_header_extension_length is inferred to be equal to 0. slice_header_extension_data_byte[i] may have any value. Decoders conforming to this version of this Specification shall ignore the values of all the slice_header_extension_data_byte[i] syntax elements. Its value does not affect decoder conformance to profiles specified in this version of specification.

As provided in Table 2, a NAL unit may include an adaptation parameter set syntax structure. Table 8 illustrates the syntax of the adaptation parameter set syntax structure provided in JVET-Q2001.

TABLE 8 De- scrip- tor adaptation_parameter_set_rbsp( ) {  adaptation_parameter_set_id u(5)  aps_params_type u(3)  if( aps_params_type = = ALF_APS )   alf_data( )  else if( aps_params_type = = LMCS_APS )   lmcs_data( )  else if( aps_params_type = = SCALING_APS )   scaling_list_data( )  aps_extension_flag u(1)  if( aps_extension_flag )   while( more_rbsp_data( ) )    aps_extension_data_flag u(1)  rbsp_trailing_bits( ) }

With respect to Table 8, JVET-Q2001 provides the following semantics:

Each APS RBSP shall be available to the decoding process prior to it being referenced, included in at least one AU with Temporand less than or equal to the Temporand of the coded slice NAL unit that refers it or provided through external means.

All APS NAL units with a particular value of adaptation_parameter_set_id and a particular value of aps_params_type within a PU, regardless of whether they are prefix or suffix APS NAL units, shall have the same content.

adaptation_parameter_set_id provides an identifier for the APS for reference by other syntax elements.

When aps_params_type is equal to ALF APS or SCALING APS, the value of adaptation_parameter_set_id shall be in the range of 0 to 7, inclusive.

When aps_params_type is equal to LMCS_APS, the value of adaptation_parameter_set_id shall be in the range of 0 to 3, inclusive.

aps_params_type specifies the type of APS parameters carried in the APS as specified in Table 9.

TABLE 9 Name of aps_params_type aps_params_type Type of APS parameters 0 ALF_APS ALF parameters 1 LMCS_APS LMCS parameters 2 SCALING_APS Scaling list parameters 3 . . . 7 Reserved Reserved

All APS NAL units with a particular value of aps_params_type, regardless of the nuh_layer_id values, share the same value space for adaptation_parameter_set_id. APS NAL units with different values of aps_params_type use separate values spaces for adaptation_parameter_set_id.

-   -   NOTE—An APS NAL unit (with a particular value of         adaptation_parameter_set_id and a particular value of         aps_params_type) can be shared across pictures, and different         slices within a picture can refer to different ALF APSs.     -   NOTE—A suffix APS NAL unit associated with a particular VCL NAL         unit (this VCL NAL unit precedes the suffix APS NAL unit in         decoding order) is not for use by the particular VCL NAL unit,         but for use by VCL NAL units following the suffix APS NAL unit         in decoding order.         aps_extension_flag equal to 0 specifies that no         aps_extension_data_flag syntax elements are present in the APS         RBSP syntax structure. aps_extension_flag equal to 1 specifies         that there are aps_extension_data_flag syntax elements present         in the APS RBSP syntax structure.         aps_extension_data_flag may have any value. Its presence and         value do not affect decoder conformance to profiles specified in         this version of this Specification. Decoders conforming to this         version of this Specification shall ignore all         aps_extension_data_flag syntax elements.

As provided in Table 8, an adaptation parameter set may include lmcs data( ). JVET-Q2001 provides where luma mapping with chroma scaling (LMCS) is a process that is applied as part of the decoding process that maps luma samples to particular values and may apply a scaling operation to the values of chroma samples. Table 10 illustrates the syntax of the lmcs_data( ) syntax structure provided in JVET-Q2001.

TABLE 10 De- scrip- tor lmcs_data ( ) {  lmcs_min_bin_idx ue(v)  lmcs_delta_max_bin_idx ue(v)  lmcs_delta_cw_prec_minus1 ue(v)  for( i = lmcs_min_bin_idx; i <= LmcsMaxBinIdx; i++ ) {   lmcs_delta_abs_cw[ i ] u(v)   if( lmcs_delta_abs_cw[ i ] ) > 0 )    lmcs_delta_sign_cw_flag[ i ] u(1)  }  lmcs_delta_abs_crs u(3)  if( lmcs_delta_abs_crs ) > 0 )   lmcs_delta_sign_crs_flag u(1) }

With respect to Table 10, JVET-Q2001 provides the following semantics:

lmcs_min_bin_idx specifics the minimum bin index used in the luma mapping with chroma scaling construction process. The value of lmcs_min_bin_idx shall be in the range of 0 to 15, inclusive. lmcs_delta_max_bin_idx specifies the delta value between 15 and the maximum bin index LmcsMaxBinIdx used in the luma mapping with chroma scaling construction process. The value of lmcs_delta_max_bin_idx shall be in the range of 0 to 15, inclusive. The value of LmcsMaxBinIdx is set equal to 15−lmcs_delta_max_bin_idx. The value of LmcsMaxBinIdx shall be greater than or equal to lmcs_min_bin_idx. lmcs_delta_cw_prec_minus1 plus 1 specifies the number of bits used for the representation of the syntax lmcs_delta_abs_cw[i]. The value of lmcs_delta_cw_prec_minus1 shall be in the range of 0 to BitDepth−2, inclusive. lmcs_delta_abs_cw[i] specifies the absolute delta codeword value for the ith bin. lmcs_delta_sign_cw_flag[i] specifies the sign of the variable lmcsDeltaCW[i] as follows:

-   -   If lmcs_delta_sign_cw_flag[i] is equal to 0, lmcsDeltaCW[i] is a         positive value.     -   Otherwise (lmcs_delta_sign_cw_flag[i] is not equal to 0),         lmcsDeltaCW[i] is a negative value.         When lmcs_delta_sign_cw_flag[i] is not present, it is inferred         to be equal to 0.         The variable OrgCW is derived as follows:     -   OrgCW=(1<<BitDepth)/16         The variable lmcsDeltaCW[i], with i=lmcs_min_bin_idx . . .         LmcsMaxBinIdx, is derived as follows:     -   lmcsDeltaCW[i]=(1-2*lmcs_delta_sign_cw_flag[i])*lmcs_delta_abs_cw[i]         The variable hncsCW[i] is derived as follows:     -   For i=0 . . . lmcs_min_bin_idx−1, lmcsCW[i] is set equal 0.     -   For i=lmcs_min_bin_idx . . . LmcsMaxBinIdx, the following         applies:         -   lmcsCW[i]=OrgCW+lmcsDeltaCW[i]             The value of lmcsCW[i] shall be in the range of (OrgCW>>3)             to (OrgCW<<3-1), inclusive.     -   For i=LmcsMaxBinldx+1 . . . 15, lmcsCW[i] is set equal 0.         It is a requirement of bitstream conformance that the following         condition is true:     -   Σ_(i=0) ¹⁵lmcsCW[i]<=(1<<BitDepth)−1         The variable InputPivot[i], with i=0 . . . 16, is derived as         follows:     -   InputPivot[i]=i*OrgCW         The variable LmcsPivot[i] with i=0 . . . 16, the variables         ScaleCoeff[i] and InvScaleCoeff[i] with i=0 . . . 15, are         derived as follows:

LmcsPivot[ 0 ] = 0; for( i = 0; i <= 15; i++ ) {  LmcsPivot[ i + 1 ] = LmcsPivot[ i ] + lmcsCW[ i ]  ScaleCoeff[ i ] = ( lmcsCW[ i ] * (1 << 11 ) + ( 1 << ( Log2(  OrgCW ) − 1 ) ) ) >> ( Log2( OrgCW ) )  if( lmcsCW[ i ] = = 0 )   InvScaleCoeff[ i ] = 0  else   InvScaleCoeff[ i ] = OrgCW * ( 1 << 11 ) / lmcsCW[ i ] } It is a requirement of bitstream conformance that, for i=lmcs_min_bin_idx . . . LmcsMaxBinIdx, when the value of LmcsPivot[i] is not a multiple of 32, the value of (LmcsPivot[i>>(BitDepth−5)) shall not be equal to the value of (LmcsPivot[i+1]>>(BitDepth−5)). lmcs_delta_abs_crs specifies the absolute codeword value of the variable lmcsDeltaCrs. The value of lmcs_delta_abs_crs shall be in the range of 0 and 7, inclusive. When not present, lmcs_delta_abs_crs is inferred to be equal to 0. lmcs_delta_sign_crs_flag specifies the sign of the variable lmcsDeltaCrs. When not present, lmcs_delta_sign_crs_flag is inferred to be equal to 0.

The variable lmcsDeltaCrs is derived as follows:

-   -   lmcsDeltaCrs=(1-2*lmcs_delta_sign_crs_flag)*lmcs_delta_abs_crs         It is a requirement of bitstream conformance that, when         lmcsCW[i] is not equal to 0, (lmcsCW[i]+lmcsDeltaCrs) is in the         range of (OrgCW>>3) to ((OrgCW<<3)−1), inclusive.         The variable ChromaScaleCoeffi[i], with i=0 . . . 15, is derived         as follows:

if( lmcsCW[ i ] = = 0 )  ChromaScaleCoeff[ i ] = ( 1 << 11 ) else  ChromaScaleCoeff[ i ] = OrgCW * ( 1 << 11 ) / ( lmcsCW[ i ] +  lmcsDeltaCrs )

JVET-Q2001 provides where the variable LmcsPivot[i] is used in a process for predicting luma samples of a picture as follows:

Inputs to this process are:

-   -   a location (xCurr, yCurr) of the top-left sample of the current         block relative to the top-left sample of the current picture,     -   a variable nCurrSw specifying the block width.     -   a variable nCurrSh specifying the block height.     -   an (nCurrSw)x(nCurrSh) array predSamples specifying the luma         predicted samples of the current block.     -   an (nCurrSw)x(nCtirrSh) array resSamples specifying the luma         residual samples of the current block.

Outputs of this process is a reconstructed luma picture sample array recSamples.

The (nCurrSw)x(nCurrSh) array of mapped predicted luma samples predMapSamples is derived as follows:

-   -   If one of the following conditions is true, predMapSamples[i][j]         is set equal to predSamples[i][j] for i=0 . . . nCurrSw−1, j=0 .         . . nCurrSh−1:         -   CuPredMode[0][xCurr][yCurr] is equal to MODE_INTRA.         -   CuPredMode[0][xCurr][yCurr] is equal to MODE_TBC.         -   CuPreclMode[0][xCurr][yCurr] is equal to MODE_PLT.         -   CuPredMode[0][xCurr][yCurr] is equal to MODE_INTER and             ciip_flag[xCurr][yCurr] is equal to 1.     -   Otherwise (CuPredMode[0][xCurr][yCurr] is equal to MODE_INTER         and ciip_flag[xCurr][yCurr] is equal to 0), the following         applies:         -   idxY=predSamples[i][j]>>Log 2(OrgCW)         -   predMapSamples[i][j]=LmcsPivot[idxY]             -   +(ScaleCoeff[idxY]*(predSamples[i][j]−InputPivot[idxY])+(1<<10))>>11             -   with i=0 . . . nCurrSw−1, j=0 . . . nCurrSh−1

The reconstructed luma picture sample recSamples is derived as follows:

-   -   recSamples[xCurr+i][yCurr+j]=Clip1(predMapSamples[i][j]+resSamples[i][j])         with i=0.nCurrSw−1, j=0 . . . nCurrSh−1

JVET-Q2001 also provides a process for inverse mapping luma samples of a picture reconstruction as follows:

Input to this process is a luma sample lumaSample.

Output of this process is a modified luma sample invLumaSample.

The value of invLumaSample is derived as follows:

-   -   If slice_lmcs_enabled_flag of the slice that contains the luma         sample lumaSample is equal to 1. the following ordered steps         apply:         -   1. The variable idxYInv is derived by invoking the             identification of piece-wise function index process for a             luma sample as specified below with lumaSample as the input             and idxYInv as the output.         -   2. The variable invSample is derived as follows:     -   invSample=InputPivot[idxYInv]+(InvScaleCoeff[idxYInv]*(lumaSample−LmcsPivot[idxYInv])+(1<<10))>>11         -   3. The inverse mapped luma sample invLumaSample is derived             as follows:     -   invLumaSample=Clip1(invSample)         -   Otherwise, invLumaSample is set equal to lumaSample.

JVET-Q2001 also provides a process for identification of piecewise function index as follows:

Input to this process is a luma sample lumaSample.

Output of this process is an index idxYInv identifying the piece to which the luma sample lumaSample belongs.

The variable idxYInv is derived as follows:

for( idxYInv = lmcs_min_bin_idx; idxYInv <= LmcsMaxBinIdx; idxYInv++ ) {  if( lumaSample < LmcsPivot [ idxYInv + 1 ] )   break } idxYInv = Min( idxYInv, 15 )

It should be noted that LMCS parameters are constrained such that when applying the inverse LMCS function, the value space can be divided into 32 bins of equal size, where for each bin, a single comparison is required to determine the index idxYInv of the pivot point to use for mapping. Further, as provided above, the lower bound on lmcs_delta_sign_cw_flag[i] is guided by two constraints:

(1) The value of lmcsCW[i] shall be in the range of OrgCW>>3 to (OrgCW<<3)−1, inclusive. (2) It is a requirement of bitstream conformance that, for i=lines min_bin_idx . . . LincsMaxBinldx, when the value of LmcsPivot[i] is not a multiple of 1<<(BitDepth−5), the value of (LmcsPivot[i]>>(BitDepth−5)) shall not be equal to the value of (LmcsPivot[i+1]>>(BitDepth−5)).

The first constraint expresses a general constraint on the range of lmcs_delta_sign_cw_flag. The second constraint guarantees that a single comparison is required to determine the pivot point index idxYInv.

In one example, according to the techniques herein, the second constraint may be removed, and the first constraint may be modified as follows:

-   -   The value of lmcsCW[i] shall be in the range of OrgCW/2-1 to         OrgCW*8-1. inclusive.

It should be noted that such a modification: simplifies conformance checks, and may also simplify encoder design; reduces the maximum value of InvScaleCoeff[i] from 16384 to 4681, thereby reducing the size of the multiplier in inverse LMCS function from Nx15 to Nx13 bits, where N is the sample bit depth; preserves existing implementation properties (e.g., single comparison the determine pivot point index); and reduces the set of possible values the LMCS function may take. However, no practical example is known where this has an impact.

The constraint related to lmcsDeltaCrs is also modified accordingly:

It is a requirement of bitstream conformance that, when lmcsCW|i| is not equal to 0, (lmcsCW|i|+lmcsDeltaCrs) is in the range of OrgCW/2-8 to OrgCW*8-1, inclusive. It should be noted that in such case the smallest value of lmcsDeltaCrs (−7) can be combined with the smallest nonzero value of lmcsCW[i](OrgCW/2-1). The reason for allowing such combination is that the number of bits required to represent ChromaScaleCoeffi[i] is the same for values of lmcsCW[i]+lmcsDeltaCrs equal to OrgCW/2-8 and OrgCW/2-1.

Alternatively, in one example according to the techniques herein, the range could be further reduced to:

-   -   The value of lmcsCW[i] shall be in the range of OrgCW/2+1 to         OrgCW*2-1. inclusive.

It should be noted that this reduced range is sufficient to represent all values encountered in common test conditions (VTM 8.0, SDR and HDR), where lmcsCW[i] ranges from OrgCW/2+14 to OrgCW*2-4.

The constraint related to lmcsDeltaCrs is also modified accordingly to this alternative range:

It is a requirement of bitstream conformance that, when lmcsCW[i] is not equal to 0, (lmcsCW[i]+lmcsDeltaCrs) is in the range of OrgCW/2+1 to OrgCW*2-1, inclusive. It should be noted that in such case the smallest value of lmcsDeltaCrs (−7) cannot be combined with the smallest nonzero value of lmcsCW[i](OrgCW/2+1).

Given the reduced range of values, the valid range of lmcs_delta_cw_prec_minus1 may also be reduced as:

The value of lmcs_delta_cw_prec_minus1 shall be in the range of 0 to BitDepth−5, inclusive.

Alternatively values of 0 may also be permitted for lmcsCW[i]. In such case, the constraint on lmcsCW[i] may be expressed as either one of the following:

-   -   When not equal to 0, the value of lmcsCW[i] shall be in the         range of OrgCW/2-1 to OrgCW*8-1, inclusive.     -   When not equal to 0, the value of lmcsCW[i] shall be in the         range of OrgCW/2+1 to OrgCW*2-1, inclusive.

As provided in Table 8, an adaptation parameter set may include scaling_list_data( ). Table 11 illustrates the syntax of the scaling_list_data( ) syntax structure provided in JVET-Q2001.

TABLE 11 De- scrip- tor scaling_list_data( ) {  scaling_matrix_for_lfnst_disabled_flag u(1)  scaling_list_chroma_present_flag u(1)  for( id = 0; id < 28; id ++ )   matrixSize = (id < 2 ) ? 2 : ( ( id < 8 ) ? 4 : 8 )   if( scaling_list_chroma_present_flag | | ( id % 3 = = 2 ) | | (   id = = 27 ) ) {    scaling_list_copy_mode_flag[ id ] u(1)    if( !scaling_list_copy_mode_flag[ id ] )     scaling_list_pred_mode_flag[ id ] u(1)    if( ( scaling_list_copy_mode_flag[ id ] | |      scaling_list_pred_mode_flag[ id ] ) && id != 0      && id != 2 && id != 8 )     scaling_list_pred_id_delta[ id ] ue(v)    if( !scaling_list_copy_mode_flag[ id ] ) {     nextCoef = 0     if( id > 13 ) {      scaling_list_dc_coef[ id − 14 ] se(v)      nextCoef += scaling_list_dc_coef[ id − 14 ]     }     for( i = 0; i < matrixSize * matrixSize; i++ ) {      x = DiagScanOrder[ 3 ][ 3 ][ i ][ 0 ]      y = DiagScanOrder[ 3 ][ 3 ][ i ][ 1 ]      if( !( id > 25 && x >= 4 && y >= 4 ) ) {       scaling_list_delta_coef[ id ][ i ] se(v)       nextCoef += scaling_list_delta_coef[ id ][ i ]      }      ScalingList[ id ][ i ] = nextCoef     }    }   }  } }

With respect to Table 11, JVET-Q2001 provides the following semantics:

scaling_matrix_for_lfnst_disabled_flag equal to 1 specifies that scaling matrices are not applied to blocks coded with LFNST (Low Frequency Non-Separable Transform). scaling_matrix_for_lfnst_disabled_flag equal to 0 specifies that the scaling matrices may apply to the blocks coded with LFNST. scaling_list_chroma_present_flag equal to 1 specifies that chroma scaling lists are present in scaling_list_data( ) scaling_list_chroma_present_flag equal to 0 specifies that chroma scaling lists are not present in scaling_list_data( ). It is a requirement of bitstream conformance that scaling_list_chroma_present_flag shall be equal to 0 when ChromaArrayType is equal to 0, and shall be equal to 1 when ChromaArrayType is not equal to 0. scaling_list_copy_mode_flag[id] equal to 1 specifics that the values of the scaling list are the same as the values of a reference scaling list. The reference scaling list is specified by scaling_list_pred_id_delta[id]. scaling_list_copy_mode_flag[id] equal to 0 specifies that scaling_list_pred_mode_flag is present. scaling_list_pred_mode_flag[id] equal to 1 specifies that the values of the scaling list can be predicted from a reference scaling list. The reference scaling list is specified by scaling_list_pred_id_delta[id]. scaling_list_pred_mode_flag[id] equal to 0 specifies that the values of the scaling list are explicitly signalled. When not present, the value of scaling_listpred_mode_flag [id] is inferred to be equal to 0. scaling_list_pred_id_delta[id] specifies the reference scaling list used to derive the predicted scaling matrix ScalingMatrixPred[id]. When not present, the value of scaling_list_pred_id_delta[id] is inferred to be equal to 0. The value of scaling_list_pred_id_delta[id] shall be in the range of 0 to maxIdDelta with maxIdDelta derived depending on id as follows:

-   -   maxIdDclta=(id<2) ? id:((id<8) ? (id−2):(id−8))         The variables refId and matrixSize are derived as follows:     -   refId=id−scaling_list_pred_id_delta[id]     -   matrixSize=(id<2) ? 2: ((id<8) ? 4:8)         The (matrixSize)x(matrixSize) array ScalingMatrixPred[x][y] with         x=0 . . . matrixSize−1, y=0 . . . matrixSize−1 and the variable         ScalingMatrixDCPred are derived as follows:     -   When both scaling_list_copy_mode_flag[id] and         scaling_list_pred_mode_flag[id] are equal to 0, all elements of         ScalingMatrixPred are set equal to 8, and the value of         ScalingMatrixDCPred is set equal to 8.     -   Otherwise, when scaling_list_pred_id_delta[id] is equal to 0,         all elements of ScalingMatrixPred are set equal to 16, and         ScalingMatrixDCPred is set equal to 16.     -   Otherwise (either scaling_list_copy_mode_flag[id] or         scaling_listpred_mode_flag[id] is equal to 1 and         scaling_listpred_id_delta[id] is greater than 0),         ScalingMatrixPred is set equal to ScalingMatrixRec[refId], and         the following applies for ScalingMatrixDCPred:     -   If refId is greater than 13. ScalingMatrixDCPred is set equal to         ScalingMatrixDCRec[refId−14].     -   Otherwise (refId is less than or equal to 13),         ScalingMatrixDCPred is set equal to ScalingMatrixPrcd[0][0].         scaling_list_dc_coef[id−14] is used to derive the value of the         variable ScalingMatrixDC[id−14] when id is greater than 13 as         follows:     -   ScalingMatrixDCRec[id−14]=(ScalingMatrixDCPred+scaling_list_dc_coef[id−14])         & 255         When not present, the value of scaling_list_dc_coef[id−14] is         inferred to be equal to 0. The value of         scaling_list_dc_coef[id−14] shall be in the range of −128 to         127, inclusive. The value of ScalingMatrixDCRec[id−14 shall be         greater than 0.         scaling_list_delta_coef└id]i┘ specifies the difference between         the current matrix coefficient ScalingList[id][i] and the         previous matrix coefficient ScalingList[id][i−1], when         scaling_list_copy_mode_flag[id] is equal to 0. The value of         scaling_list_delta_coef[id][i] shall be in the range of −128 to         127, inclusive. When scaling_list_copy_mode_flag└id┘ is equal to         1, all elements of ScalingList└id┘ are set equal to 0. The         (matrixSize)x(matrixSize) array ScalingMatrixRec[id] is derived         as follows:     -   ScalingMatrixRec[id][x][y]=(ScalingMatrixPred[x][y]+ScalingList[id][k])         & 255         -   with k=0 . . . (matrixSize*matrixSize−1),             -   x=DiagScanOrder[Log 2(matrixSize)][Log                 2(matrixSize)][k][0], and             -   y=DiagScanOrder┌Log 2(matrixSize)┐┌Log                 2(matrixSize)┐┌k┐┌1┐                 The value of ScalingMatrixRec[id][x][y] shall be greater                 than 0.

JVET-Q2001 provides where scaling is the process of multiplying transform coefficient levels by a factor, resulting in transform coefficients. JVET-Q2001 provides where a scaling list is a list that associates each index associated with a transform coefficient prior to the application of a transform in the decoding process with a scale factor for the scaling process. JVET-Q2001 provides where ScalingMatrixRec[id][x][y] is used in a scaling process for transform coefficients as follows:

Inputs to this process are:

-   -   a luma location (xTbY, yTbY) specifying the top-left sample of         the current luma transform block relative to the top-left luma         sample of the current picture,     -   a variable nTbW specifying the transform block width.     -   a variable nTbH specifying the transform block height,     -   a variable predMode specifying the prediction mode of the coding         unit,     -   a variable cIdx specifying the colour component of the current         block.         Output of this process is the (nTbW)x(nTbH) array d of scaled         transform coefficients with elements d[x][y].

The quantization parameter qP and the variable QpActOffset are derived as follows:

-   -   If cIdx is equal to 0, the following applies:         -   qP=Qp′_(Y)         -   QpActOffset=cu_act_enabled_flag└xTbY┘└yTbY┘ ?−5:0     -   Otherwise, if TuCResMode[xTbY][yTbY] is equal to 2, the         following applies:         -   qP=Qp′_(CbCr)         -   QpActOffset=cu_act_enabled_flag┌xTbY┐┌yTbY┐? 1:0     -   Otherwise, if cIdx is equal to 1, the following applies:         -   qP=Qp′_(Cb)         -   QpActOffset=cu_act_enabled_flag[xTbY][yTbY]? 1:0     -   Otherwise (cIdx is equal to 2), the following applies:         -   qP=Qp′_(Cr)         -   QpActOffset=cu_act_enabled_flag[xTbY][yTbY] ? 3:0

The quantization parameter qP is modified and the variables rectNonTsFlag and bdShift are derived as follows:

-   -   If transform_skip_flag[xTbY][yTbY][cIdx] is equal to 0, the         following applies:         -   qP=Clip3(0, 63+QpBdOffset, qP+QpActOffset)         -   rectNonTsFlag=(((Log 2(nTbW)+Log 2(nTbH)) & 1)==1) ? 1:0         -   bdShift=BitDepth+rectNonTsFlag+((Log 2(nTbW)+Log             2(nTbH))/2)−5+phdep_quant_enabled_flag     -   Otherwise (transform_skip_flag┌xTbY┐┌yTbY┐┌cIdx┐ is equal to 1),         the following applies:         -   qP=Clip3(QpPrimeTsMin, 63+QpBdOffset, qP+QpActOffset)         -   rectNonTsFlag=0         -   bdShift=10

The variable bdOffset is derived as follows:

-   -   bdOffset=(1<<bdShift)>>1

The list levelScale[ ][ ] is specified as levelScale[j][k]={{40, 45, 51, 57, 64, 72}, {57, 64, 72, 80, 90, 102} } with j=0 . . . 1, k=0 . . . 5.

The (nTbW)x(nTbH) array dz is set equal to the (nTbW)x(nTbH) array TransCoeffLevel[xTbY][yTbY][cIdx]. For the derivation of the scaled transform coefficients d[x][y] with x=0 . . . nTbW−1, y=0 . . . nTbH−1, the following applies:

-   -   The intermediate scaling factor m[x][y] is derived as follows:         -   If one or more of the following conditions are true, m[x][y]             is set equal to 16:             -   sps_scaling_list_enabled_flag is equal to 0.             -   ph_scaling_list_present_flag is equal to 0.             -   transform_skip_flag┌xTbY┐┌yTbY┐┌cIdx┐ is equal to 1.             -   scaling matrix_for_list_disabled_flag is equal to 1 and                 ApplyLfnstFlag is equal to 1.             -   Otherwise, the following applies:                 -   The variable id is derived based on predMode, cldx,                     nTbW, and nTbH as specified in Table 12 and the                     variable log 2MatrixSize is derived as follows:                 -    log 2MatrixSize=(id<2) ? 1:(id<8) ? 2:3                 -   The scaling factor m└x┘└y┘ is derived as follows:                 -    m[x][y]=ScalingMatrixRec[id][i][j]                 -    with i=(x<<log 2MatrixSize)>>Log 2(nTbW),                 -    j=(y<<log 2MatrixSize)>>Log 2(nTbH)                 -   If id is greater than 13 and both x and y are equal                     to 0, m[0][0] is further modified as follows:                 -    m[0][0]=ScalingMatrixDCRec[id−14]     -   NOTE—A quantization matrix element m[x][y] can be zeroed out         when any of the following conditions is true         -   x is greater than 31         -   y is greater than 31         -   The decoded tu is not coded by default transform mode (i.e.             transform type is not equal to 0) and x is greater than 15         -   The decoded tu is not coded by default transform mode (i.e.             transform type is not equal to 0) and y is greater than 15     -   The scaling factor ls[x][y] is derived as follows:         -   If ph_dep_quant_enabled_flag is equal to 1 and             transform_skip_flag┌xTbY┐┌yTbY┐┌cIdx┐ is equal to 0, the             following applies:             -   ls[x][y]=(m[x][y]*levelScale[rectNonTsFlag][(qP+1) %                 6]<<((qp+1)/6)         -   Otherwise (ph_dep_quant_enabled_flag is equal to 0 or             transform_skip_flag┌xTbY┐┌yTbY┐┌cIdx┐ is equal to 1), the             following applies:             -   ls[x][y]=(m[x][y]*levelScale[rectNonTsFlag][qP %                 6])<<(qP/6)     -   When BdpanFlag[xTbY][yYbY][cIdx] is equal to 1, dz[x][y] is         modified as follows:         -   If BdpcmDir[xTbY][yYbY][cIdx] is equal to 0 and x is greater             than 0, the following applies:             -   dz[x][y]=Clip3(CoeffMin, CoeffMax, dz[x−1][y]+dz[x][y])     -   Otherwise, if BdpcmDir|xTbY∥yTbY∥cldx| is equal to 1 and y is         greater than 0, the following applies:         -   dz[x][y]=Clip3(CoeffMin, CoeffMax, dz[x][y]−1+dz[x][y])             -   The value dnc[x][y] is derived as follows:         -   dnc└x┘└y┘=(dx└x┘└y┘*ls└x┘└y┘+bdOffset)>>bdShift             -   The scaled transform coefficient d[x][y] is derived as                 follows:                 -   d┌x┐┌y┐=Clip3(CoeffMin, CoeffMax, dnc┌x┐┌y┐)

TABLE 12 max( nTbW, nTbH ) 2 4 8 16 32 64 predMode = cIdx = 0 (Y) 2 8 14 20 26 MODE_INTRA cIdx = 1 (Cb) 3 9 15 21 21 cIdx = 2 (Cr) 4 10 16 22 22 predMode = cIdx = 0 (Y) 5 11 17 23 27 MODE_INTER cIdx = 1 (Cb) 0 6 12 18 24 24 (INTER, IBC) cIdx = 2 (Cr) 1 7 13 19 25 25

As provided above, in JVET-Q2001, a PH syntax structure may be present in the slice header of a VCL NAL unit or in a PH NAL unit of the current PU. When a PH syntax structure is present in the slice header signaling of particular syntax elements in the slice header may become redundant and thus inefficient. For example, as provided above, syntax element slice_lmcs_enabled_flag which specifies whether luma mapping with chroma scaling is enabled for the current slice is present in the slice header when syntax element ph_lmcs_enabled_flag equal specifies that luma mapping with chroma scaling is enabled for all slices associated with the PH. Similarly, syntax element slice_sealing_list_present_flag which specifies whether the scaling_list_data used for the current slice is derived based on the scaling_list_data contained in the referenced scaling list APS luma is present in the slice header when syntax element ph_scaling_list_present_flag specifies that the scaling_list_data used for the slices associated with the PH is derived based on the scaling_list_data contained in the referenced scaling list APS. When a picture header is included in the slice header, the flags slice_lmcs_enabled_flag and slice_sealing_list_present_flag do not need to be signaled because the picture header flags ph_lmcs_enabled_flag and ph_sealing_list_present_flag are sufficient to control LMCS and scaling list signaling for the slice. According to the techniques herein, the presence of one or more syntax elements in a slice header may be based on whether the slice header includes a picture header.

FIG. 1 is a block diagram illustrating an example of a system that may be configured to code (i.e., encode and/or decode) video data according to one or more techniques of this disclosure. System 100 represents an example of a system that may encapsulate video data according to one or more techniques of this disclosure. As illustrated in FIG. 1 , system 100 includes source device 102, communications medium 110, and destination device 120. In the example illustrated in FIG. 1 , source device 102 may include any device configured to encode video data and transmit encoded video data to communications medium 110. Destination device 120 may include any device configured to receive encoded video data via communications medium 110 and to decode encoded video data. Source device 102 and/or destination device 120 may include computing devices equipped for wired and/or wireless communications and may include, for example, set top boxes, digital video recorders, televisions, desktop, laptop or tablet computers, gaming consoles, medical imagining devices, and mobile devices, including, for example, smartphones, cellular telephones, personal gaming devices.

Communications medium 110 may include any combination of wireless and wired communication media, and/or storage devices. Communications medium 110 may include coaxial cables, fiber optic cables, twisted pair cables, wireless transmitters and receivers, routers, switches, repeaters, base stations, or any other equipment that may be useful to facilitate communications between various devices and sites. Communications medium 110 may include one or more networks. For example, communications medium 110 may include a network configured to enable access to the World Wide Web, for example, the Internet. A network may operate according to a combination of one or more telecommunication protocols. Telecommunications protocols may include proprietary aspects and/or may include standardized telecommunication protocols. Examples of standardized telecommunications protocols include Digital Video Broadcasting (DVB) standards, Advanced Television Systems Committee (ATSC) standards, Integrated Services Digital Broadcasting (ISDB) standards, Data Over Cable Service Interface Specification (DOCSIS) standards, Global System Mobile Communications (GSM) standards, code division multiple access (CDMA) standards, 3rd Generation Partnership Project (3GPP) standards, European Telecommunications Standards Institute (ETSI) standards, Internet Protocol (IP) standards, Wireless Application Protocol (WAP) standards, and Institute of Electrical and Electronics Engineers (IEEE) standards.

Storage devices may include any type of device or storage medium capable of storing data. A storage medium may include a tangible or non-transitory computer-readable media. A computer readable medium may include optical discs, flash memory, magnetic memory, or any other suitable digital storage media. In some examples, a memory device or portions thereof may be described as non-volatile memory and in other examples portions of memory devices may be described as volatile memory. Examples of volatile memories may include random access memories (RAM), dynamic random access memories (DRAM), and static random access memories (SRAM). Examples of non-volatile memories may include magnetic hard discs, optical discs, floppy discs, flash memories, or forms of electrically programmable memories (EPROM) or electrically erasable and programmable (EEPROM) memories. Storage device(s) may include memory cards (e.g., a Secure Digital (SD) memory card), internal/external hard disk drives, and/or internal/external solid state drives. Data may be stored on a storage device according to a defined file format.

FIG. 4 is a conceptual drawing illustrating an example of components that may be included in an implementation of system 100. In the example implementation illustrated in FIG. 4 , system 100 includes one or more computing devices 402A-402N, television service network 404, television service provider site 406, wide area network 408, local area network 410, and one or more content provider sites 412A-412N. The implementation illustrated in FIG. 4 represents an example of a system that may be configured to allow digital media content, such as, for example, a movie, a live sporting event, etc., and data and applications and media presentations associated therewith to be distributed to and accessed by a plurality of computing devices, such as computing devices 402A-402N. In the example illustrated in FIG. 4 , computing devices 402A-402N may include any device configured to receive data from one or more of television service network 404, wide area network 408, and/or local area network 410. For example, computing devices 402A-402N may be equipped for wired and/or wireless communications and may be configured to receive services through one or more data channels and may include televisions, including so-called smart televisions, set top boxes, and digital video recorders. Further, computing devices 402A-402N may include desktop, laptop, or tablet computers, gaming consoles, mobile devices, including, for example, “smart” phones, cellular telephones, and personal gaming devices.

Television service network 404 is an example of a network configured to enable digital media content, which may include television services, to be distributed. For example, television service network 404 may include public over-the-air television networks, public or subscription-based satellite television service provider networks, and public or subscription-based cable television provider networks and/or over the top or Internet service providers. It should be noted that although in some examples television service network 404 may primarily be used to enable television services to be provided, television service network 404 may also enable other types of data and services to be provided according to any combination of the telecommunication protocols described herein. Further, it should be noted that in some examples, television service network 404 may enable two-way communications between television service provider site 406 and one or more of computing devices 402A-402N. Television service network 404 may comprise any combination of wireless and/or wired communication media. Television service network 404 may include coaxial cables, fiber optic cables, twisted pair cables, wireless transmitters and receivers, routers, switches, repeaters, base stations, or any other equipment that may be useful to facilitate communications between various devices and sites. Television service network 404 may operate according to a combination of one or more telecommunication protocols. Telecommunications protocols may include proprietary aspects and/or may include standardized telecommunication protocols. Examples of standardized telecommunications protocols include DVB standards, ATSC standards, ISDB standards, DTMB standards, DMB standards, Data Over Cable Service Interface Specification (DOCSIS) standards, HbbTV standards, W3C standards, and UPnP standards.

Referring again to FIG. 4 , television service provider site 406 may be configured to distribute television service via television service network 404. For example, television service provider site 406 may include one or more broadcast stations, a cable television provider, or a satellite television provider, or an Internet-based television provider. For example, television service provider site 406 may be configured to receive a transmission including television programming through a satellite uplink/downlink. Further, as illustrated in FIG. 4 , television service provider site 406 may be in communication with wide area network 408 and may be configured to receive data from content provider sites 412A-412N. It should be noted that in some examples, television service provider site 406 may include a television studio and content may originate therefrom.

Wide area network 408 may include a packet based network and operate according to a combination of one or more telecommunication protocols. Telecommunications protocols may include proprietary aspects and/or may include standardized telecommunication protocols. Examples of standardized telecommunications protocols include Global System Mobile Communications (GSM) standards, code division multiple access (CDMA) standards, 3^(rd) Generation Partnership Project (3GPP) standards, European Telecommunications Standards Institute (ETSI) standards, European standards (EN), IP standards, Wireless Application Protocol (WAP) standards, and Institute of Electrical and Electronics Engineers (IEEE) standards, such as, for example, one or more of the IEEE 802 standards (e.g., Wi-Fi). Wide area network 408 may comprise any combination of wireless and/or wired communication media. Wide area network 408 may include coaxial cables, fiber optic cables, twisted pair cables, Ethernet cables, wireless transmitters and receivers, routers, switches, repeaters, base stations, or any other equipment that may be useful to facilitate communications between various devices and sites. In one example, wide area network 408 may include the Internet. Local area network 410 may include a packet based network and operate according to a combination of one or more telecommunication protocols. Local area network 410 may be distinguished from wide area network 408 based on levels of access and/or physical infrastructure. For example, local area network 410 may include a secure home network.

Referring again to FIG. 4 , content provider sites 412A-412N represent examples of sites that may provide multimedia content to television service provider site 406 and/or computing devices 402A-402N. For example, a content provider site may include a studio having one or more studio content servers configured to provide multimedia files and/or streams to television service provider site 406. In one example, content provider sites 412A-412N may be configured to provide multimedia content using the IP suite. For example, a content provider site may be configured to provide multimedia content to a receiver device according to Real Time Streaming Protocol (RTSP), HTTP, or the like. Further, content provider sites 412A-412N may be configured to provide data, including hypertext based content, and the like, to one or more of receiver devices computing devices 402A-402N and/or television service provider site 406 through wide area network 408. Content provider sites 412A-412N may include one or more web servers. Data provided by data provider site 412A-412N may be defined according to data formats.

Referring again to FIG. 1 , source device 102 includes video source 104, video encoder 106, data encapsulator 107, and interface 108. Video source 104 may include any device configured to capture and/or store video data. For example, video source 104 may include a video camera and a storage device operably coupled thereto. Video encoder 106 may include any device configured to receive video data and generate a compliant bitstream representing the video data. A compliant bitstream may refer to a bitstream that a video decoder can receive and reproduce video data therefrom. Aspects of a compliant bitstream may be defined according to a video coding standard. When generating a compliant bitstream video encoder 106 may compress video data. Compression may be lossy (discernible or indiscernible to a viewer) or lossless. FIG. 5 is a block diagram illustrating an example of video encoder 500 that may implement the techniques for encoding video data described herein. It should be noted that although example video encoder 500 is illustrated as having distinct functional blocks, such an illustration is for descriptive purposes and does not limit video encoder 500 and/or sub-components thereof to a particular hardware or software architecture. Functions of video encoder 500 may be realized using any combination of hardware, firmware, and/or software implementations.

Video encoder 500 may perform intra prediction coding and inter prediction coding of picture areas, and, as such, may be referred to as a hybrid video encoder. In the example illustrated in FIG. 5 , video encoder 500 receives source video blocks. In some examples, source video blocks may include areas of picture that has been divided according to a coding structure. For example, source video data may include macroblocks, CTUs, CBs, sub-divisions thereof, and/or another equivalent coding unit. In some examples, video encoder 500 may be configured to perform additional subdivisions of source video blocks. It should be noted that the techniques described herein are generally applicable to video coding, regardless of how source video data is partitioned prior to and/or during encoding. In the example illustrated in FIG. 5 , video encoder 500 includes summer 502, transform coefficient generator 504, coefficient quantization unit 506, inverse quantization and transform coefficient processing unit 508, summer 510, intra prediction processing unit 512, inter prediction processing unit 514, filter unit 516, and entropy encoding unit 518. As illustrated in FIG. 5 , video encoder 500 receives source video blocks and outputs a bitstream.

In the example illustrated in FIG. 5 , video encoder 500 may generate residual data by subtracting a predictive video block from a source video block. The selection of a predictive video block is described in detail below. Summer 502 represents a component configured to perform this subtraction operation. In one example, the subtraction of video blocks occurs in the pixel domain. Transform coefficient generator 504 applies a transform, such as a discrete cosine transform (DCT), a discrete sine transform (DST), or a conceptually similar transform, to the residual block or subdivisions thereof (e.g., four 8×8 transforms may be applied to a 16×16 array of residual values) to produce a set of residual transform coefficients. Transform coefficient generator 504 may be configured to perform any and all combinations of the transforms included in the family of discrete trigonometric transforms, including approximations thereof. Transform coefficient generator 504 may output transform coefficients to coefficient quantization unit 506. Coefficient quantization unit 506 may be configured to perform quantization of the transform coefficients. The quantization process may reduce the bit depth associated with some or all of the coefficients. The degree of quantization may alter the rate-distortion (i.e., bit-rate vs. quality of video) of encoded video data. The degree of quantization may be modified by adjusting a quantization parameter (QP). A quantization parameter may be determined based on slice level values and/or CU level values (e.g., CU delta QP values). QP data may include any data used to determine a QP for quantizing a particular set of transform coefficients. As illustrated in FIG. 5 , quantized transform coefficients (which may be referred to as level values) are output to inverse quantization and transform coefficient processing unit 508. Inverse quantization and transform coefficient processing unit 508 may be configured to apply an inverse quantization and an inverse transformation to generate reconstructed residual data. As illustrated in FIG. 5 , at summer 510, reconstructed residual data may be added to a predictive video block. In this manner, an encoded video block may be reconstructed and the resulting reconstructed video block may be used to evaluate the encoding quality for a given prediction, transformation, and/or quantization. Video encoder 500 may be configured to perform multiple coding passes (e.g., perform encoding while varying one or more of a prediction, transformation parameters, and quantization parameters). The rate-distortion of a bitstream or other system parameters may be optimized based on evaluation of reconstructed video blocks. Further, reconstructed video blocks may be stored and used as reference for predicting subsequent blocks.

Referring again to FIG. 5 , intra prediction processing unit 512 may be configured to select an intra prediction mode for a video block to be coded. Intra prediction processing unit 512 may be configured to evaluate a frame and determine an intra prediction mode to use to encode a current block. As described above, possible intra prediction modes may include planar prediction modes, DC prediction modes, and angular prediction modes. Further, it should be noted that in some examples, a prediction mode for a chroma component may be inferred from a prediction mode for a luma prediction mode. Intra prediction processing unit 512 may select an intra prediction mode after performing one or more coding passes. Further, in one example, intra prediction processing unit 512 may select a prediction mode based on a rate-distortion analysis. As illustrated in FIG. 5 , intra prediction processing unit 512 outputs intra prediction data (e.g., syntax elements) to entropy encoding unit 518 and transform coefficient generator 504. As described above, a transform performed on residual data may be mode dependent (e.g., a secondary transform matrix may be determined based on a prediction mode).

Referring again to FIG. 5 , inter prediction processing unit 514 may be configured to perform inter prediction coding for a current video block. Inter prediction processing unit 514 may be configured to receive source video blocks and calculate a motion vector for PUs of a video block. A motion vector may indicate the displacement of a prediction unit of a video block within a current video frame relative to a predictive block within a reference frame. Inter prediction coding may use one or more reference pictures. Further, motion prediction may be uni-predictive (use one motion vector) or bi-predictive (use two motion vectors). Inter prediction processing unit 514 may be configured to select a predictive block by calculating a pixel difference determined by, for example, sum of absolute difference (SAD), sum of square difference (SSD), or other difference metrics. As described above, a motion vector may be determined and specified according to motion vector prediction. Inter prediction processing unit 514 may be configured to perform motion vector prediction, as described above. Inter prediction processing unit 514 may be configured to generate a predictive block using the motion prediction data. For example, inter prediction processing unit 514 may locate a predictive video block within a frame buffer (not shown in FIG. 5 ). It should be noted that inter prediction processing unit 514 may further be configured to apply one or more interpolation filters to a reconstructed residual block to calculate sub-integer pixel values for use in motion estimation. Inter prediction processing unit 514 may output motion prediction data for a calculated motion vector to entropy encoding unit 518.

Referring again to FIG. 5 , filter unit 516 receives reconstructed video blocks and coding parameters and outputs modified reconstructed video data. Filter unit 516 may be configured to perform deblocking and/or Sample Adaptive Offset (SAO) filtering. SAO filtering is a non-linear amplitude mapping that may be used to improve reconstruction by adding an offset to reconstructed video data. It should be noted that as illustrated in FIG. 5 , intra prediction processing unit 512 and inter prediction processing unit 514 may receive modified reconstructed video block via filter unit 216. Entropy encoding unit 518 receives quantized transform coefficients and predictive syntax data (i.e., intra prediction data and motion prediction data). It should be noted that in some examples, coefficient quantization unit 506 may perform a scan of a matrix including quantized transform coefficients before the coefficients are output to entropy encoding unit 518. In other examples, entropy encoding unit 518 may perform a scan. Entropy encoding unit 518 may be configured to perform entropy encoding according to one or more of the techniques described herein. In this manner, video encoder 500 represents an example of a device configured to generate encoded video data according to one or more techniques of this disclosure.

Referring again to FIG. 1 , data encapsulator 107 may receive encoded video data and generate a compliant bitstream, e.g., a sequence of NAL units according to a defined data structure. A device receiving a compliant bitstream can reproduce video data therefrom. Further, as described above, sub-bitstream extraction may refer to a process where a device receiving a ITU-T H.265 compliant bitstream forms a new ITU-T H.265 compliant bitstream by discarding and/or modifying data in the received bitstream. It should be noted that the term conforming bitstream may be used in place of the term compliant bitstream. In one example, data encapsulator 107 may be configured to generate syntax according to one or more techniques described herein. It should be noted that data encapsulator 107 need not necessary be located in the same physical device as video encoder 106. For example, functions described as being performed by video encoder 106 and data encapsulator 107 may be distributed among devices illustrated in FIG. 4 .

As described above. the signaling provided in JVET-Q2001 for signaling syntax elements in a slice header when a PH syntax structure is present in the slice header may be less than ideal. Table 13 illustrates an example of the relevant portion of a slice_header( ) syntax structure according to the techniques herein where syntax element slice_lmcs_enabled_flag is not signaled when picture_header_in_slice_header_flag is equal to 1 and instead its value is inferred in this case.

TABLE 13 De- scrip- tor slice_header( ) { ...  if( ph_lmcs_enabled_flag &&  !picture_header_in_slice_header_flag )   slice_lmcs_enabled_flag u(1)  if( ph_scaling_list_present_flag)   slice_scaling_list_present_flag u(1)  if( entry_point_offsets_present_flag && NumEntryPoints >  0 ) {   offset_len_minus1 ue(v)   for( i = 0; i < NumEntryPoints; i++ )    entry_point_offset_minus1[ i ] u(v)  }  if( slice_header_extension_present_flag ) {   slice_header_extension_length ue(v)   for( i = 0; i < slice_header_extension_length; i++)    slice_header_extension_data_byte[ i ] u(8)  }  byte_alignment( ) }

With respect to Table 13, the semantics may be based on the semantics provided above, with the following example semantics for syntax elements slice_lmcs_enabled_flag:

slice_lmcs_enabled_flag equal to 1 specifies that luma mapping with chroma scaling is enabled for the current slice. slice_lmcs_enabled_flag equal to 0 specifies that luma mapping with chroma scaling is not enabled for the current slice. When slice_lmcs_enabled_flag is not present it is inferred to be equal to ph_lmcs_enabled_flag.

Table 14 illustrates an example of the relevant portion of a slice header( ) syntax structure according to the techniques herein where syntax element slice_scaling_list_present_flag is not signaled when picture_header_in_slice_header_flag is equal to 1 and instead its value is inferred in this case.

TABLE 14 De- scrip- tor slice_header( ) { ...  if( ph_lmcs_enabled_flag)   slice_lmcs_enabled_flag u(1)  if( ph_scaling_list_present_flag &&  !picture_header_in_slice_header_flag)   slice_scaling_list_present_flag u(1)  if( entry_point_offsets_present_flag && NumEntryPoints >  0 ) {   offset_len_minus1 ue(v)   for( i = 0; i < NumEntryPoints; i++ )    entry_point_offset_minus1[ i ] u(v)  }  if( slice_header_extension_present_flag ) {   slice_header_extension_length ue(v)   for( i = 0; i < slice_header_extension_length; i++)    slice_header_extension_data_byte[ i ] u(8)  }  byte_alignment( ) }

With respect to Table 14, the semantics may be based on the semantics provided above, with the following example semantics for syntax elements slice_scaling_list_present_flag:

slice_scaling_list_present_flag equal to 1 specifies that the scaling_list_data used for the current slice is derived based on the scaling_list_data contained in the referenced scaling list APS with aps_params_type equal to SCALING_APS and adaptation_parameter_set_id equal to ph_scaling_list_aps_id. slice_scaling_list_present_flag equal to 0 specifies that the scaling_list_data used for the current picture is the default scaling_list_data derived as specified. When slice_scaling_list_present_flag is not present it is inferred to be equal to ph_scaling_list_present_flag.

Further with respect to Table 14, the derivation of the intermediate scaling factor m[x][y] described in the scaling process described above may be as follows:

-   -   If one or more of the following conditions are true, m|x∥y| is         set equal to 16:         -   sps_scaling_list_enabled_flag is equal to 0.         -   slice_scaling_list_present_flag is equal to 0.         -   transform_skip_flag[xTbY][yTbY][cTdx] is equal to 1.         -   scaling_matrix_for_lfnst_disabled_flag is equal to 1 and             ApplyLfnstFlag is equal to 1.     -   Otherwise, the L applies:         -   The variable id is derived based on predMode, cIdx, nTbW,             and nTbH as specified in Table 38 and the variable log             2MatrixSize is derived as follows:             -   log 2MatrixSize=(id<2) ? 1:(id<8) ? 2:3         -   The scaling factor m[x][y] is derived as follows:             -   m[x][y]=ScalingMatrixRec[id][i][j]                 -   with i=(x<<log 2MatrixSize)>>Log 2(nTbW),                 -    j=(y<<log 2MatrixSize)>>Log 2(nTbH)         -   If id is greater than 13 and both x and y are equal to 0,             m|0∥0| is further modified as follows:             -   m[0][0]=ScalingMatrixDCRec[id−14]

It should be noted that in some examples, the flag slice_scaling_list_present_flag may instead be called slice_scaling_list_enabled_flag.

Further, it should be noted that the examples described with respect to Table 13 and Table 14 may be combined as provided in Table 15A or in Table 15B.

TABLE 15A De- scrip- tor slice_header( ) { ...  if( ph_lmcs_enabled_flag &&  !picture_header_in_slice_header_flag)   slice_lmcs_enabled_flag u(1)  if( ph_scaling_list_present_flag &&  !picture_header_in_slice_header_flag)   slice_scaling_list_present_flag u(1)  if( entry_point_offsets_present_flag && NumEntryPoints >  0 ) {   offset_len_minus1 ue(v)   for( i = 0; i < NumEntryPoints; i++ )    entry_point_offset_minus1[ i ] u(v)  }  if( slice_header_extension_present_flag ) {   slice_header_extension_length ue(v)   for( i = 0; i < slice_header_extension_length; i++)    slice_header_extension_data_byte[ i ] u(8)  }  byte_alignment( ) }

TABLE 15B De- scrip- tor slice_header( ) {  if(!picture_header_in_slice_header_flag) {   if( ph_lmcs_enabled_flag)    slice_lmcs_enabled_flag u(1)   if( ph_scaling_list_present_flag)    slice_scaling_list_present_flag u(1) }   if( entry_point_offsets_present_flag &&   NumEntryPoints > 0 ) {    offset_len_minus1 ue(v)    for( i = 0; i < NumEntryPoints; i++ )     entry_point_offset_minus1[ i ] u(v)   }   if( slice_header_extension_present_flag ) {    slice_header_extension_length ue(v)    for( i = 0; i < slice_header_extension_length; i++)     slice_header_extension_data_byte[ i ] u(8)   }   byte_alignment( ) }

As described above, in an IRAP picture, all slices must be intra slices. Referring to the picture header syntax structure, picture_header_structure( ), provided in Table 5, it is asserted that it is redundant and potentially unclear to be allowed to signal a value equal to 1 for syntax element ph_inter_slice_allowed_flag for IRAP pictures. When syntax element gdr_or_irap_pic_flag is equal to 1 and syntax element gdr_pic_flag is equal to 0, the current picture is an IRAP picture and in one example, according to the techniques herein, in this case, ph_inter_slice_allowed_flag may not be signaled and inferred to be equal to 0. Table 16A illustrates an example of the relevant syntax of the picture header syntax structure for this example.

TABLE 16A De- scrip- tor picture_header_structure( ) {  gdr_or_irap_pic_flag u(1)  if( gdr_or_irap_pic_flag )   gdr_pic_flag u(1)  if( !gdr_or_irap_pic_flag | | gdr_pic_flag )   ph_inter_slice_allowed_flag u(1)  if( ph_inter_slice_allowed_flag )   ph_intra_slice_allowed_flag u(1)  non_reference_picture_flag u(1)  ph_pic_parameter_set_id ue(v)  ph_pic_order_cnt_lsb u(v)  if( gdr_or_irap_pic_flag ) ...

With respect to Table 16A, the semantics may be based on the semantics provided above with respect to Table 5 and the following example semantics:

gdr_or_irap_pic_flag equal to 1 specifies that the current picture is a GDR or IRAP picture. gdr_or_irap_pic_flag equal to 0 specifies that the current picture may or may not be an IRAP picture and is not a GDR picture.

gdr_pic_flag equal to 1 specifies the picture associated with the PH is a GDR picture. gdr_pic_flag equal to 0 specifies that the picture associated with the PH is not a GDR picture. When not present, the value of gdr_pic_flag is inferred to be equal to 0. When gdr_enabled_flag is equal to 0, the value of gdr_pic_flag shall be equal to 0.

ph_inter_slice_allowed_flag equal to 0 specifies that all coded slices of the picture have slice_type equal to 2. ph_inter_slice_allowed_flag equal to 1 specifies that there may or may not be one or more coded slices in the picture that have slice_type equal to 0 or 1. When not present, the value of ph_inter_slice_allowed_flag is inferred to be equal to 0.

ph_intra_slice_allowed_flag equal to 0 specifies that all coded slices of the picture have slice_type equal to 0 or 1. ph_intra_slice_allowed_flag equal to 1 specifies that there may or may not be one or more coded slices in the picture that have slice_type equal to 2.When not present, the value of ph_intra_slice_allowed_flag is inferred to be equal to 1.

In another example, with respect to Table 16A the syntax element ph_inter_slice_allowed_flag may be signalled unconditionally and independent of the value of gdr_irap_pic_flag and gdr_pic_flag. In this case there may be a conformance constraint:

When syntax element gdr_or_irap_pic_flag is equal to 1 and syntax element gdr_pic_flag is equal to 0, ph_inter_slice_allowed_flag shall be equal to 0.

It should be noted that when a picture is a GDR picture with recovery_poc_cnt equal to 0, all slices are intra slices.

In one example, according to the techniques herein, in this case, the position of recover_poc_cnt syntax element in the picture header syntax structure may be moved and the condition for signaling ph_inter_slice_allowed_flag may be further modified such that it is not signaled and inferred for GDR pictures with recovery_poc_cnt equal to 0. Table 16B illustrates an example of the relevant syntax of the picture header syntax structure for this example.

TABLE 16B De- scrip- tor picture_header_structure( ) {  gdr_or_irap_pic_flag u(1)  if( gdr_or_irap_pic_flag && gdr_enabled_flag )   gdr_pic_flag u(1)  if( gdr_pic_flag )   recovery_poc_cnt ue(v)  if ( !gdr_or_irap_pic_flag | |  (gdr_pic_flag && recovery_poc_cnt > 0) )   ph_inter_slice_allowed_flag u(1)  if( ph_inter_slice_allowed_flag )   ph_intra_slice_allowed_flag u(1)  non_reference_picture_flag u(1)  ph_pic_parameter_set_id ue(v)  ph_pic_order_cnt_lsb u(v)  if( gdr_or_irap_pic_flag )   no_output_of_prior_pics_flag u(1) ...

With respect to Table 16B, the semantics may be based on the semantics provided above with respect to Table 16A and the following example semantics:

ph_inter_slice_allowed_flag equal to 0 specifies that all coded slices of the picture have slice_type equal to 2. ph_inter_slice_allowed_flag equal to 1 specifies that there may or may not be one or more coded slices in the picture that have slice_type equal to 0 or 1. When not present, the value of ph_inter_slice_allowed_flag is inferred to be equal to 0. In another example, with respect to Table 16B the syntax element ph_inter_slice_allowed_flag may be signalled unconditionally and independent of the value of gdr_irap_pic_flag and gdr_pic_flag. In this case there may be one or more conformance constraints as follows: When syntax element gdr_or_irap_pic_flag is equal to 1 and syntax element gdr_pic_flag is equal to 0, ph_inter_slice_allowed_flag shall be equal to 0. When syntax element syntax element gdr_pic_flag is equal to 1, and syntax element recovery_poc_cnt is equal to 0, ph_inter_slice_allowed_flag shall be equal to 0.

In another example, syntax element gdr_or_irap_pic_flag may be replaced with a syntax element irap_pic_flag having semantics based on the following:

irap_pic_flag equal to 1 specifies that the current picture is an IRAP picture. irap_pic_flag equal to 0 specifies that the current picture may or may not be an IRAP picture.

Table 16C illustrates an example of the relevant syntax of the picture header syntax structure for this example.

TABLE 16C De- scrip- tor picture_header_structure( ) {  irap_pic_flag u(1)  if( !irap_pic_flag ) {   gdr_pic_flag u(1)   ph_inter_slice_allowed_flag u(1)  }  if( ph_inter_slice_allowed_flag )   ph_intra_slice_allowed_flag u(1)  non_reference_picture_flag u(1)  ph_pic_parameter_set_id ue(v)  ph_pic_order_cnt_lsb u(v)  if( gdr_or_irap_pic_flag )   no_output_of_prior_pics_flag u(1)  if( gdr_pic_flag )   recovery_poc_cnt ue(v)  for( i = 0; i < NumExtraPhBits; i++ )   ph_extra_bit[ i ] u(1)

With respect to Table 16C, the semantics may be based on the semantics provided above.

In another example, with respect to Table 16C the syntax element gdr_pic_flag may be signalled unconditionally and independent of the value of irap_pic_flag. In this case there may be a conformance constraint:

When irap_pic_flag is equal to 1, grap_pic_flag shall be equal to 0.

In another example, with respect to Table 16C the syntax element ph_inter_slice_allowed_flag may be signalled unconditionally and independent of the value of irap_pic_flag. In this case there may be a conformance constraint:

When irap_pic_flag is equal to 1, ph_inter_slice_allowed_flag shall be equal to 0.

Table 16D illustrates one example of the relevant syntax of the picture header syntax structure according to the techniques herein.

TABLE 16D De- scrip- tor picture_header_structure( ) {  gdr_or_irap_pic_flag u(1)  if( gdr_or_irap_pic_flag )   gdr_pic_flag u(1)  if( !gdr_or_irap_pic_flag | | gdr_pic_flag | | nuh_layer_id >  0 )   ph_inter_slice_allowed_flag u(1)  if( ph_inter_slice_allowed_flag )   ph_intra_slice_allowed_flag u(1)  non_reference_picture_flag u(1)  ph_pic_parameter_set_id ue(v)  ph_pic_order_cnt_lsb u(v)  if( gdr_or_irap_pic_flag ) ...

With respect to Table 16D, the semantics may be based on the semantics provided above and the following example semantics:

The PH syntax structure contains information that is common for all slices of the coded picture associated with the PH syntax structure.

gdr_or_irap_pic_flag equal to 1 specifies that the current picture is a GDR or TRAP picture. gdr_or_irap_pic_flag equal to 0 specifies that the current picture may or may not be an TRAP picture and is not a GDR picture. gdr_pic_flag equal to 1 specifics the picture associated with the PH is a GDR picture. gdr_pic_flag equal to 0 specifics that the picture associated with the PH is not a GDR picture. When not present, the value of gdr_pic_flag is inferred to be equal to 0. When gdr_enabled_flag is equal to 0, the value of gdr_pic_flag shall be equal to 0. ph_inter_slice_allowed_flag equal to 0 specifies that all coded slices of the picture have slice_type equal to 2. ph_inter_slice_allowed_flag equal to 1 specifies that there may or may not be one or more coded slices in the picture that have slice_type equal to 0 or 1. When not present, the value of ph_inter_slice_allowed_flag is inferred to be equal to 0. ph_intra_slice_allowed_flag equal to 0 specifies that all coded slices of the picture have slice_type equal to 0 or 1. ph_intra_slice_allowed_flag equal to 1 specifies that there may or may not be one or more coded slices in the picture that have slice_type equal to 2.When not present, the value of ph_intra_slice_allowed_flag is inferred to be equal to 1. In one example, the above condition for signaling of ph_inter_slice_allowed_flag may be changed to: if((!gdr_or_irap_pic_flag gdr_pic_flag) (nuh_layer_id !=0)).

Table 16E illustrates one example of the relevant syntax of the picture header syntax structure according to the techniques herein.

TABLE 16E De- scrip- tor picture_header_structure( ) {  gdr_or_irap_pic_flag u(1)  if( gdr_or_irap_pic_flag )   gdr_pic_flag u(1)  if( !gdr_or_irap_pic_flag | | gdr_pic_flag | |   vps_independent_layer_flag[ GeneralLayerIdx[   nuh_layer_id ] ] = = 0 )   ph_inter_slice_allowed_flag u(1)  if( ph_inter_slice_allowed_flag )   ph_intra_slice_allowed_flag u(1)  non_reference_picture_flag u(1)  ph_pic_parameter_set_id ue(v)  ph_pic_order_cnt_lsb u(v)  if( gdr_or_irap_pic_flag ) ...

With respect to Table 16E, the semantics may be based on the semantics provided above and the following example semantics:

The PH syntax structure contains information that is common for all slices of the coded picture associated with the PH syntax structure.

gdr_or_irap_pic_flag equal to 1 specifies that the current picture is a GDR or IRAP picture. gdr_or_irap_pic_flag equal to 0 specifies that the current picture may or may not be an IRAP picture and is not a GDR picture. gdr_pic_flag equal to 1 specifies the picture associated with the PH is a GDR picture. gdr_pic_flag equal to 0 specifies that the picture associated with the PH is not a GDR picture. When not present, the value of gdr_pic_flag is inferred to be equal to 0. When gdr_enabled_flag is equal to 0, the value of gdr_pic_flag shall be equal to 0. ph_inter_slice_allowed_flag equal to 0 specifies that all coded slices of the picture have slice_type equal to 2. ph_inter_slice_allowed_flag equal to 1 specifies that there may or may not be one or more coded slices in the picture that have slice_type equal to 0 or 1. When not present, the value of ph_inter_slice_allowed_flag is inferred to be equal to 0. ph_intra_slice_allowed_flag equal to 0 specifies that all coded slices of the picture have slice_type equal to 0 or 1. ph_intra_slice_allowed_flag equal to 1 specifies that there may or may not be one or more coded slices in the picture that have slice_type equal to 2.When not present, the value of ph_intra_slice_allowed_flag is inferred to be equal to 1. In one example the above condition for signaling of ph_inter_slice_allowed_flag may be changed to: if((!gdr_or_irap_pic_flag gdr_pic_flag) (sps_video_parameter_set_id !=0))

In this manner, source device 102 represents an example of a device configured to signal a syntax element in a slice header indicating whether a picture header is included in the slice header and conditionally signal one or more syntax elements in the slice header based on whether a picture header is included in the slice header.

Referring again to FIG. 1 , interface 108 may include any device configured to receive data generated by data encapsulator 107 and transmit and/or store the data to a communications medium. Interface 108 may include a network interface card, such as an Ethernet card, and may include an optical transceiver, a radio frequency transceiver, or any other type of device that can send and/or receive information. Further, interface 108 may include a computer system interface that may enable a file to be stored on a storage device. For example, interface 108 may include a chipset supporting Peripheral Component Interconnect (PCI) and Peripheral Component Interconnect Express (PCIe) bus protocols, proprietary bus protocols, Universal Serial Bus (USB) protocols, I²C, or any other logical and physical structure that may be used to interconnect peer devices.

Referring again to FIG. 1 , destination device 120 includes interface 122, data decapsulator 123, video decoder 124, and display 126. Interface 122 may include any device configured to receive data from a communications medium. Interface 122 may include a network interface card, such as an Ethernet card, and may include an optical transceiver, a radio frequency transceiver, or any other type of device that can receive and/or send information. Further, interface 122 may include a computer system interface enabling a compliant video bitstream to be retrieved from a storage device. For example, interface 122 may include a chipset supporting PCI and PCIe bus protocols, proprietary bus protocols, USB protocols, I²C, or any other logical and physical structure that may be used to interconnect peer devices. Data decapsulator 123 may be configured to receive and parse any of the example syntax structures described herein.

Video decoder 124 may include any device configured to receive a bitstream (e.g., a sub-bitstream extraction) and/or acceptable variations thereof and reproduce video data therefrom. Display 126 may include any device configured to display video data. Display 126 may comprise one of a variety of display devices such as a liquid crystal display (LCD), a plasma display, an organic light emitting diode (OLED) display, or another type of display. Display 126 may include a High Definition display or an Ultra High Definition display. It should be noted that although in the example illustrated in FIG. 1 , video decoder 124 is described as outputting data to display 126, video decoder 124 may be configured to output video data to various types of devices and/or subcomponents thereof. For example, video decoder 124 may be configured to output video data to any communication medium, as described herein.

FIG. 6 is a block diagram illustrating an example of a video decoder that may be configured to decode video data according to one or more techniques of this disclosure (e.g., the decoding process for reference-picture list construction described above). In one example, video decoder 600 may be configured to decode transform data and reconstruct residual data from transform coefficients based on decoded transform data. Video decoder 600 may be configured to perform intra prediction decoding and inter prediction decoding and, as such, may be referred to as a hybrid decoder. Video decoder 600 may be configured to parse any combination of the syntax elements described above in Tables 1-16E. Video decoder 600 may decode a picture based on or according to the processes described above, and further based on parsed values in Tables 1-16E.

In the example illustrated in FIG. 6 , video decoder 600 includes an entropy decoding unit 602, inverse quantization unit 604, inverse transform processing unit 606, intra prediction processing unit 608, inter prediction processing unit 610, summer 612, post filter unit 614, and reference buffer 616. Video decoder 600 may be configured to decode video data in a manner consistent with a video coding system. It should be noted that although example video decoder 600 is illustrated as having distinct functional blocks, such an illustration is for descriptive purposes and does not limit video decoder 600 and/or sub-components thereof to a particular hardware or software architecture. Functions of video decoder 600 may be realized using any combination of hardware, firmware, and/or software implementations.

As illustrated in FIG. 6 , entropy decoding unit 602 receives an entropy encoded bitstream. Entropy decoding unit 602 may be configured to decode syntax elements and quantized coefficients from the bitstream according to a process reciprocal to an entropy encoding process. Entropy decoding unit 602 may be configured to perform entropy decoding according any of the entropy coding techniques described above. Entropy decoding unit 602 may determine values for syntax elements in an encoded bitstream in a manner consistent with a video coding standard. As illustrated in FIG. 6 , entropy decoding unit 602 may determine a quantization parameter, quantized coefficient values, transform data, and prediction data from a bitstream. In the example, illustrated in FIG. 6 , inverse quantization unit 604 and inverse transform processing unit 606 receive a quantization parameter, quantized coefficient values, transform data, and prediction data from entropy decoding unit 602 and output reconstructed residual data.

Referring again to FIG. 6 , reconstructed residual data may be provided to summer 612. Summer 612 may add reconstructed residual data to a predictive video block and generate reconstructed video data. A predictive video block may be determined according to a predictive video technique (i.e., intra prediction and inter frame prediction). Intra prediction processing unit 608 may be configured to receive intra prediction syntax elements and retrieve a predictive video block from reference buffer 616. Reference buffer 616 may include a memory device configured to store one or more frames of video data. Intra prediction syntax elements may identify an intra prediction mode, such as the intra prediction modes described above. Inter prediction processing unit 610 may receive inter prediction syntax elements and generate motion vectors to identify a prediction block in one or more reference frames stored in reference buffer 616. Inter prediction processing unit 610 may produce motion compensated blocks, possibly performing interpolation based on interpolation filters. Identifiers for interpolation filters to be used for motion estimation with sub-pixel precision may be included in the syntax elements. Inter prediction processing unit 610 may use interpolation filters to calculate interpolated values for sub-integer pixels of a reference block. Post filter unit 614 may be configured to perform filtering on reconstructed video data. For example, post filter unit 614 may be configured to perform deblocking and/or Sample Adaptive Offset (SAO) filtering, e.g., based on parameters specified in a bitstream. Further, it should be noted that in some examples, post filter unit 614 may be configured to perform proprietary discretionary filtering (e.g., visual enhancements, such as, mosquito noise reduction). As illustrated in FIG. 6 , a reconstructed video block may be output by video decoder 600. In this manner, video decoder 600 represents an example of a device configured to parse a syntax element in a slice header indicating whether a picture header is included in the slice header and conditionally parse one or more syntax elements in the slice header based on whether a picture header is included in the slice header.

In one or more examples, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media, which corresponds to a tangible medium such as data storage media, or communication media including any medium that facilitates transfer of a computer program from one place to another, e.g., according to a communication protocol. In this manner, computer-readable media generally may correspond to (1) tangible computer-readable storage media which is non-transitory or (2) a communication medium such as a signal or carrier wave. Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementation of the techniques described in this disclosure. A computer program product may include a computer-readable medium.

By way of example, and not limitation, such computer-readable storage media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. It should be understood, however, that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transitory media, but are instead directed to non-transitory, tangible storage media. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor,” as used herein may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. In addition, in some aspects, the functionality described herein may be provided within dedicated hardware and/or software modules configured for encoding and decoding, or incorporated in a combined codec. Also, the techniques could be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC) or a set of ICs (e.g., a chip set). Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, various units may be combined in a codec hardware unit or provided by a collection of interoperative hardware units, including one or more processors as described above, in conjunction with suitable software and/or firmware.

Moreover, each functional block or various features of the base station device and the terminal device used in each of the aforementioned embodiments may be implemented or executed by a circuitry, which is typically an integrated circuit or a plurality of integrated circuits. The circuitry designed to execute the functions described in the present specification may comprise a general-purpose processor, a digital signal processor (DSP), an application specific or general application integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic, or a discrete hardware component, or a combination thereof. The general-purpose processor may be a microprocessor, or alternatively, the processor may be a conventional processor, a controller, a microcontroller or a state machine. The general-purpose processor or each circuit described above may be configured by a digital circuit or may be configured by an analogue circuit. Further, when a technology of making into an integrated circuit superseding integrated circuits at the present time appears due to advancement of a semiconductor technology, the integrated circuit by this technology is also able to be used.

Various examples have been described. These and other examples are within the scope of the following claims.

CROSS REFERENCE

This Nonprovisional application claims priority under 35 U.S.C. § 119 on provisional Applications No. 62/966,916 on Jan. 28, 2020, No. 62/991,530 on Mar. 18, 2020, No. 62/992,778 on Mar. 20, 2020 and No. 63/009,793 on Apr. 14, 2020, the entire contents of which are hereby incorporated by reference. 

1. A method of decoding video data, the method including: decoding an enabled flag syntax element specifying whether a luma mapping with chroma scaling is enabled for all slices associated with a picture header syntax structure; receiving a slice header; decoding a first flag syntax element specifying whether the picture header syntax structure is present in the slice header; decoding a second flag syntax element specifying a luma mapping is used for a current slice or a luma mapping with a chroma scalling is not used for a current slice, in a case that (i) the enabled flag syntax element indicates the luma mapping with chroma scaling is enabled and (ii) the first flag syntax element indicates the picture header syntax structure is not present in the slice header.
 2. (canceled)
 3. (canceled)
 4. A device for decoding video data, the device comprising: a processor, and a memory associated with the processor; wherein the processor is configured to: decode an enabled flag syntax element specifying whether a luma mapping with chroma scaling is enabled for all slices associated with a picture header syntax structure; receive a slice header; decode a first flag syntax element specifying whether the picture header syntax structure is present in the slice header; decode a second flag syntax element specifying a luma mapping is used for a current slice or a luma mapping with a chroma scalling is not used for a current slice, in a case that (i) the enabled flag syntax element indicates the luma mapping with chroma scaling is enabled and (ii) the first flag syntax element indicates the picture header syntax structure is not present in the slice header.
 5. A device for encoding image data, the device comprising: a processor, and a memory associated with the processor; wherein the processor is configured to perform: encode an enabled flag syntax element specifying whether a luma mapping with chroma scaling is enabled for all slices associated with a picture header syntax structure; encode a first flag syntax element specifying whether the picture header syntax structure is present in a slice header; and encode a second flag syntax element, specifying a luma mapping is used for a current slice or a luma mapping with a chroma scalling is not used for a current slice, in a case that (i) the enabled flag syntax element indicates the luma mapping with chroma scaling is enabled and (ii) the first flag syntax element indicates the picture header syntax structure is not present in the slice header.
 6. The device of claim 4, wherein the processor is configured to: decode a present flag syntax element specifying whether scaling information is present for all slices associated with the picture header syntax structure; and decode a third flag syntax element specifying whether the scaling information for a current slice is derived, in a case that (i) the present flag syntax element indicates the scaling information is present and (ii) the first flag syntax element indicates the picture header syntax structure is not present in the slice header.
 7. The device of claim 6, wherein the second flag syntax element and the third flag syntax element are not decoded, in a case that the first flag syntax element indicates the picture header syntax structure is present in the slice header.
 8. The device of claim 4, wherein the first flag syntax element indicates the picture header syntax structure is not present in the slice header, in a case that a value of the first flag syntax element is equal to a first value.
 9. A method of encoding image data, the method including: encoding a enabled flag syntax element specifying whether a luma mapping with chroma scaling is enabled for all slices associated with a picture header syntax structure; encoding a first flag syntax element specifying whether the picture header syntax structure is present in a slice header; and encoding a second flag syntax element, specifying a luma mapping is used for a current slice or a luma mapping with a chroma scalling is not used for a current slice, in a case that (i) the enabled flag syntax element indicates the luma mapping with chroma scaling is enabled and (ii) the first flag syntax element indicates the picture header syntax structure is not present in the slice header. 